uu.seUppsala University Publications
Change search
Refine search result
123 1 - 50 of 113
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Adams, Christopher
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Kjeldsen, Frank
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Patriksson, Alexandra
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van Der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Gräslund, Astrid
    Papadopolous, Evangelos
    Zubarev, Roman
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Probing Solution-Phase and Gas-Phase Structures of Trp-cage Cations by Chiral Substitution and Spectroscopic Techniques2006In: International Journal of Mass Spectrometry, ISSN 1387-3806, E-ISSN 1873-2798, Vol. 253, no 3, p. 263-273Article in journal (Refereed)
    Abstract [en]

    The relevance of gas-phase protein structure to its solution structure is of the utmost importance in studying biomolecules by mass spectrometry. D-Amino acid substitutions within a minimal protein. Trp-cage. were used to correlate solution-phase properties as measured by circular dichroism with solution/gas-phase conformational features of protein cations probed via charge state distribution (CSD) in electrospray ionization. and gas-phase features revealed by tandem mass spectrometry (MS/MS). The gas-phase features were additionally supported by force-field molecular dynamics simulations. CD data showed that almost any single-residue D-substitution destroys the most prominent CD feature of the "native" all-L isomer, alpha-helicity. CSD was able to qualitatively assess the degree of compactness of solution-phase molecular structures. CSD results were consistent with the all-L form being the most compact in solution among all studied stereoisomers except for the D-Asn(1) isomer. D-substitutions of the aromatic Y(3), W(6) and Q(5) residues generated the largest deviations in CSD data among single amino acid substitutions. consistent with the critical role of these residues in Trp-cage stability. Electron capture dissociation of the stereoisomer dications gave an indication that some gas-phase structural features of Trp-cage are similar to those in solution. This result is supported by MDS data oil five of the studied stereoisomer dications in the gas-phase. The MDS-derived minimum-energy structures possessed more extensive hydrogen bonding than the solution-phase structure of the native form, deviating from the latter by 3-4 angstrom and were not 'inside-out' compared to native structures. MDS data could be correlated with CD data and even with ECD results. which aided in providing a long-range structural constraint for MDS. The overall conclusion is the general resemblance, despite the difference on the detailed level, of the preferred structures in both phases for the mini protein Trp-cage.

  • 2. Andersson, Magnus
    et al.
    Vincent, Jonathan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Davidsson, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Neutze, Richard
    A proposed time-resolved X-ray scattering approach to track local and global conformational changes in membrane transport proteins2008In: Structure, ISSN 0969-2126, E-ISSN 1878-4186, Vol. 16, no 1, p. 21-28Article in journal (Refereed)
    Abstract [en]

    Time-resolved X-ray scattering has emerged as a powerful technique for studying the rapid structural dynamics of small molecules in solution. Membrane-protein-catalyzed transport processes frequently couple large-scale conformational changes of the transporter with local structural changes perturbing the uptake and release of the transported substrate. Using light-driven halide ion transport catalyzed by halorhodopsin as a model system, we combine molecular dynamics simulations with X-ray scattering calculations to demonstrate how small-molecule time-resolved X-ray scattering can be extended to the study of membrane transport processes. In particular, by introducing strongly scattering atoms to label specific positions within the protein and substrate, the technique of time-resolved wide-angle X-ray scattering can reveal both local and global conformational changes. This approach simultaneously enables the direct visualization of global rearrangements and substrate movement, crucial concepts that underpin the alternating access paradigm for membrane transport proteins.

  • 3.
    Bashardanesh, Zahedeh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Impact of Dispersion Coefficient on Simulations of Proteins and Organic Liquids2018In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 122, no 33, p. 8018-8027Article in journal (Refereed)
    Abstract [en]

    In the context of studies of proteins under crowding conditions, it was found that there is a tendency of simulated proteins to coagulate in a seemingly unphysical manner. This points to an imbalance in the protein-protein or protein-water interactions. One way to resolve this is to strengthen the protein-water Lennard-Jones interactions. However, it has also been suggested that dispersion interactions may have been systematically overestimated in force fields due to parameterization with a short cutoff. Here, we test this proposition by performing simulations of liquids and of proteins in solution with systematically reduced C-6 (dispersion constant in a 12-6 Lennard-Jones potential) and evaluate the properties. We find that simulations of liquids with either a dispersion correction or explicit long-range Lennard-Jones interactions need little or no correction to the dispersion constant to reproduce the experimental density. For simulations of proteins, a significant reduction in the dispersion constant is needed to reduce the coagulation, however. Because the protein- and liquid force fields share atom types, at least to some extent, another solution for the coagulation problem may be needed, either through including explicit polarization or through strengthening protein-water interactions.

  • 4. Behzadi, Hadi
    et al.
    Olyai, Mohamad Reza Talei Bavil
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Probing (13)C chemical shielding tensors in cryptolepine and two bromo-substituted analogs for antiplasmodial activity2011In: Journal of Molecular Modeling, ISSN 1610-2940, E-ISSN 0948-5023, Vol. 17, no 12, p. 3289-3297Article in journal (Refereed)
    Abstract [en]

    Density functional theory calculations were applied to investigate (13)C chemical shielding tensors in cryptolepine and its bromo-substituted analogs, 2-bromocryptolepine and 2,7-dibromocryptolepine. The fact that bromo-substituted cryptolepine shows higher antiplasmodial activity than cryptolepine raises the question of whether this effect can be related to the electronic properties around carbon atoms. The results show that changes to the principal components of the shielding tensors upon substitution are significant. In particular, sigma (33) is the most affected tensor for carbons in the substituted ring, which could be related to the increased antiplasmodial activity of bromosubstituted cryptolepine. The analyses were also focused on atomic charges and dipole moment.

  • 5.
    Behzadi, Hadi
    et al.
    Kharazmi Univ, Fac Chem, Dept Phys Chem, Tehran, Iran.
    Roonasi, Payman
    Kharazmi Univ, Fac Chem, Dept Phys Chem, Tehran, Iran.
    Taghipour, Khatoon Assle
    Kharazmi Univ, Fac Chem, Dept Phys Chem, Tehran, Iran.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Manzetti, Sergio
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Fjordforsk AS Inst Sci & Technol, N-6894 Midtun, Vangsnes, Norway.
    Relationship between electronic properties and drug activity of seven quinoxaline compounds: A DFT study2015In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 1091, p. 196-202Article in journal (Refereed)
    Abstract [en]

    The quantum chemical calculations at the DFT/B3LYP level of theory were carried out on seven quinoxaline compounds, which have been synthesized as anti-Mycobacterium tuberculosis agents. Three conformers were optimized for each compound and the lowest energy structure was found and used in further calculations. The electronic properties including E-HOMO, E-LUMO and related parameters as well as electron density around oxygen and nitrogen atoms were calculated for each compound. The relationship between the calculated electronic parameters and biological activity of the studied compounds were investigated. Six similar quinoxaline derivatives with possible more drug activity were suggested based on the calculated electronic descriptors. A mechanism was proposed and discussed based on the calculated electronic parameters and bond dissociation energies.

  • 6. Behzadi, Hadi
    et al.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Esrafili, Mehdi D
    Parsafar, Gholam Abbas
    Hadipour, Nasser L
    Role of spin state on the geometry and nuclear quadrupole resonance parameters in hemin complex2008In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 134, no 3, p. 200-206Article in journal (Refereed)
    Abstract [en]

    Theoretical calculations of structural parameters, 57Fe, 14N and 17 O electric field gradient (EFG) tensors for full size-hemin group have been carried out using density functional theory. These calculations are intended to shed light on the difference between the geometry parameters, nuclear quadrupole coupling constants (QCC), and asymmetry parameters (eta Q) found in three spin states of hemin; doublet, quartet and sextet. The optimization results reveal a significant change for propionic groups and porphyrin plane in different spin states. It is found that all principal components of EFG tensor at the iron site are sensitive to electronic and geometry structures. A relationship between the EFG tensor at the 14N and 17 O sites and the spin state of hemin complex is also detected.

  • 7.
    Bellissent-Funel, Marie-Claire
    et al.
    CEA Saclay, CNRS, Lab Leon Brillouin, F-91191 Gif Sur Yvette, France..
    Hassanali, Ali
    Abdus Salaam Int Ctr Theoret Phys, Condensed Matter & Stat Phys, I-34151 Trieste, Italy..
    Havenith, Martina
    Ruhr Univ Bochum, Fac Chem & Biochem, Univ Str 150 Bldg NC 7-72, D-44780 Bochum, Germany..
    Henchman, Richard
    Univ Manchester, Manchester Inst Biotechnol, 131 Princess St, Manchester M1 7DN, Lancs, England..
    Pohl, Peter
    Johannes Kepler Univ Linz, Gruberstr 40, A-4020 Linz, Austria..
    Sterpone, Fabio
    Inst Biol Physicochim, Lab Biochim Theor, 13 Rue Pierre & Marie Curie, F-75005 Paris, France..
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Xu, Yao
    Ruhr Univ Bochum, Fac Chem & Biochem, Univ Str 150 Bldg NC 7-72, D-44780 Bochum, Germany..
    Garcia, Angel E.
    Los Alamos Natl Lab, Ctr Non Linear Studies, Los Alamos, NM 87545 USA..
    Water Determines the Structure and Dynamics of Proteins2016In: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 116, no 13, p. 7673-7697Article, review/survey (Refereed)
    Abstract [en]

    Water is an essential participant in the stability, structure, dynamics, and function of proteins and other biomolecules. Thermodynamically, changes in the aqueous environment affect the stability of biomolecules. Structurally, water participates chemically in the catalytic function of proteins and nucleic acids and physically in the collapse of the protein chain during folding through hydrophobic collapse and mediates binding through the hydrogen bond in complex formation. Water is a partner that slaves the dynamics of proteins, and water interaction with proteins affect their dynamics. Here we provide a review of the experimental and computational advances over the past decade in understanding the role of water in the dynamics, structure, and function of proteins. We focus on the combination of X-ray and neutron crystallography, NMR, terahertz spectroscopy, mass spectroscopy, thermodynamics, and computer simulations to reveal how water assist proteins in their function. The recent advances in computer simulations and the enhanced sensitivity of experimental tools promise major advances in the understanding of protein dynamics, and water surely will be a protagonist.

  • 8.
    Bergh, Magnus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Model for the Dynamics of a Water Cluster in an X-ray Free Electron Laser Beam2004In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 70, no 5:1, p. 051904-Article in journal (Refereed)
    Abstract [en]

    A microscopic sample placed into a focused x-ray free electron laser beam will explode due to strong ionization on a femtosecond time scale. The dynamics of this Coulomb explosion has been modeled by Neutze et al. [Nature (London) 406, 752 (2000)] for a protein, using computer simulations. The results suggest that by using ultrashort exposures, structural information may be collected before the sample is destroyed due to radiation damage. In this paper a method is presented to include the effect of screening by free electrons in the sample in a molecular dynamics simulation. The electrons are approximated by a classical gas, and the electron distribution is calculated iteratively from the Poisson-Boltzmann equation. Test simulations of water clusters reveal the details of the explosion dynamics, as well as the evolution of the free electron gas during the beam exposure. We find that inclusion of the electron gas in the model slows down the Coulomb explosion. The hydrogen atoms leave the sample faster than the oxygen atoms, leading to a double layer of positive ions. A considerable electron density is located between these two layers. The fact that the hydrogens are found to explode much faster than the oxygens means that the diffracting part of the sample stays intact somewhat longer than the sample as a whole.

  • 9. Bjorling, Alexander
    et al.
    Niebling, Stephan
    Marcellini, Moreno
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    van der Spoel, David
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Westenhoff, Sebastian
    Deciphering Solution Scattering Data with Experimentally Guided Molecular Dynamics Simulations2015In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 11, no 2, p. 780-787Article in journal (Refereed)
    Abstract [en]

    Time-resolved X-ray solution scattering is an increasingly popular method to measure conformational changes in proteins. Extracting structural information from the resulting difference X-ray scattering data is a daunting task. We present a method in which the limited but precious information encoded in such scattering curves is combined with the chemical knowledge of molecular force fields. The molecule of interest is then refined toward experimental data using molecular dynamics simulation. Therefore, the energy landscape is biased toward conformations that agree with experimental data. We describe and verify the method, and we provide an implementation in GROMACS.

  • 10.
    Bálint, Mónika
    et al.
    University of Pécs, Medical School, Department of Pharmacology and Pharmacotherapy; Eötvös Loránd University, Department of Biochemistry.
    Jeszenői, Norbert
    University of Pécs, Center for Neuroscience, MTA NAP -B Molecular Neuroendocrinology Group, Institute of Physiology.
    Horváth, István
    University of Szeged, Chemistry Doctoral School.
    van der Spoel, David
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Hetényi, Csaba
    University of Pécs, Medical School, Department of Pharmacology and Pharmacotherapy.
    Systematic exploration of multiple drug binding sites2017In: Journal of Cheminformatics, ISSN 1758-2946, E-ISSN 1758-2946, Vol. 9, no 65Article in journal (Refereed)
    Abstract [en]

    Background: Targets with multiple (prerequisite or allosteric) binding sites have an increasing importance in drug design. Experimental determination of atomic resolution structures of ligands weakly bound to multiple binding sites is often challenging. Blind docking has been widely used for fast mapping of the entire target surface for multiple binding sites. Reliability of blind docking is limited by approximations of hydration models, simplified handling of molecular flexibility, and imperfect search algorithms.

    Results: To overcome such limitations, the present study introduces Wrap 'n' Shake (WnS), an atomic resolution method that systematically "wraps" the entire target into a monolayer of ligand molecules. Functional binding sites are extracted by a rapid molecular dynamics shaker. WnS is tested on biologically important systems such as mitogenactivated protein, tyrosine-protein kinases, key players of cellular signaling, and farnesyl pyrophosphate synthase, a target of antitumor agents.

  • 11.
    Caleman, Carl
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Huldt, Gösta
    Ortiz, Carlos
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Materials Science, Materials Theory.
    Maia, Filipe R. N. C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Marklund, Erik G.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Parak, Fritz G.
    van der Spool, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Nanocrystal imaging using intense and ultrashort X-ray pulsesManuscript (preprint) (Other (popular science, discussion, etc.))
    Abstract [en]

    Structural studies of biological macromolecules are severely limited by radiation damage. Traditional crystallography curbs the effects of damage by spreading damage over many copies of the molecule of interest in the crystal. X-ray lasers offer an additional opportunity for limiting damage by out-running damage processes with ultrashort and very intense X-ray pulses. Such pulses may allow the imaging of single molecules, clusters or nanoparticles, but coherent flash imaging will also open up new avenues for structural studies on nano- and micro-crystalline substances. This paper addresses the potentials and limitations of nanocrystallography with extremely intense coherent X-ray pulses. We use urea nanocrystals as a model for generic biological substances, and simulate the primary and secondary ionization dynamics in the crystalline sample. The results establish conditions for diffraction experiments as a function of X-ray fluence, pulse duration, and the size of nanocrystals.

  • 12. Caleman, Carl
    et al.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hong, Minyan
    Hub, Jochen S.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Costa, Luciano T.
    van der Spoer, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant2012In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 8, no 1, p. 61-74Article in journal (Refereed)
    Abstract [en]

    The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on experimental data, in order to be able to compare simulation results to them. To compute the heat capacities, we applied the two phase thermodynamics method (Lin et al. J. Chem. Phys. 2003, 119, 11792), which allows one to compute thermodynamic properties on the basis of the density of states as derived from the velocity autocorrelation function. The method is implemented in a new utility within the GROMACS molecular simulation package, named g_dos, and a detailed expose of the underlying equations is presented. The purpose of this work is to establish the state of the art of two popular force fields, OPLS/AA (all-atom optimized potential for liquid simulation) and GAFF (generalized Amber force field), to find common bottlenecks, i.e., particularly difficult molecules, and to serve as a reference point for future force field development. To make for a fair playing field, all molecules were evaluated with the same parameter settings, such as thermostats and barostats, treatment of electrostatic interactions, and system size (1000 molecules). The densities and enthalpy of vaporization from an independent data set based on simulations using the CHARMM General Force Field (CGenFF) presented by Vanommeslaeghe et al. (J. Comput. Chem. 2010, 31, 671) are included for comparison. We find that, overall, the OPLS/AA force field performs somewhat better than GAFF, but there are significant issues with reproduction of the surface tension and dielectric constants for both force fields.

  • 13. Cavalieri, A L
    et al.
    Fritz, D M
    Lee, S H
    Bucksbaum, P H
    Reis, D A
    Rudati, J
    Mills, D M
    Fuoss, P H
    Stephenson, G B
    Kao, C C
    Siddons, D P
    Lowney, D P
    Macphee, A G
    Weinstein, D
    Falcone, R W
    Pahl, R
    Als-Nielsen, J
    Blome, C
    Düsterer, S
    Ischebeck, R
    Schlarb, H
    Schulte-Schrepping, H
    Tschentscher, Th
    Schneider, J
    Hignette, O
    Sette, F
    Sokolowski-Tinten, K
    Chapman, H N
    Lee, R W
    Hansen, T N
    Synnergren, O
    Larsson, J
    Techert, S
    Sheppard, J
    Wark, J S
    Bergh, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Caleman, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Huldt, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    van der Spoel, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Timneanu, N
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Hajdu, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Akre, R A
    Bong, E
    Emma, P
    Krejcik, P
    Arthur, J
    Brennan, S
    Gaffney, K J
    Lindenberg, A M
    Luening, K
    Hastings, J B
    Clocking femtosecond X rays.2005In: Phys Rev Lett, ISSN 0031-9007, Vol. 94, no 11, p. 114801-Article in journal (Refereed)
    Abstract [en]

    Linear-accelerator-based sources will revolutionize ultrafast x-ray science due to their unprecedented brightness and short pulse duration. However, time-resolved studies at the resolution of the x-ray pulse duration are hampered by the inability to precisely synchronize an external laser to the accelerator. At the Sub-Picosecond Pulse Source at the Stanford Linear-Accelerator Center we solved this problem by measuring the arrival time of each high energy electron bunch with electro-optic sampling. This measurement indirectly determined the arrival time of each x-ray pulse relative to an external pump laser pulse with a time resolution of better than 60 fs rms.

  • 14. Chapman, Henry N.
    et al.
    Barty, Anton
    Bogan, Michael J.
    Boutet, Sebastien
    Frank, Matthias
    Hau-Riege, Stefan P.
    Marchesini, Stefano
    Woods, Bruce W.
    Bajt, Sasa
    Benner, Henry
    London, Richard A.
    Ploenjes, Elke
    Kuhlmann, Marion
    Treusch, Rolf
    Duesterer, Stefan
    Tschentscher, Thomas
    Schneider, Jochen R.
    Spiller, Eberhard
    Moeller, Thomas
    Bostedt, Christoph
    Hoener, Matthias
    Shapiro, David A.
    Hodgson, Keith O.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Bergh, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Huldt, Gösta
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Seibert, Marvin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Maia, Filipe
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Lee, Richard W.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Szöke, Abraham
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär Biofysik.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär Biofysik.
    Femtosecond diffractive imaging with a soft-X-ray free-electron laser2006In: Nature Physics, ISSN 1745-2473, E-ISSN 1745-2481, Vol. 2, no 12, p. 839-843Article in journal (Refereed)
    Abstract [en]

    Theory predicts(1-4) that, with an ultrashort and extremely bright coherent X-ray pulse, a single diffraction pattern may be recorded from a large macromolecule, a virus or a cell before the sample explodes and turns into a plasma. Here we report the first experimental demonstration of this principle using the FLASH soft-X-ray free-electron laser. An intense 25 fs, 4 x 10(13) W cm(-2) pulse, containing 10(12) photons at 32 nm wavelength, produced a coherent diffraction pattern from a nanostructured non-periodic object, before destroying it at 60,000 K. A novel X-ray camera assured single-photon detection sensitivity by filtering out parasitic scattering and plasma radiation. The reconstructed image, obtained directly from the coherent pattern by phase retrieval through oversampling(5-9), shows no measurable damage, and is reconstructed at the diffraction-limited resolution. A three-dimensional data set may be assembled from such images when copies of a reproducible sample are exposed to the beam one by one(10).

  • 15.
    dos Santos Soares, Ricardo de Oliveira
    et al.
    Fac Med Marilia, Marilia, Brazil..
    Bortot, Leandro Oliveira
    Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Fis & Quim, Grp Fis Biol, Ribeirao Preto, Brazil..
    van Der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Caliri, Antonio
    Univ Sao Paulo, Fac Ciencias Farmaceut Ribeirao Preto, Dept Fis & Quim, Grp Fis Biol, Ribeirao Preto, Brazil..
    Membrane vesiculation induced by proteins of the dengue virus envelope studied by molecular dynamics simulations2017In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 29, no 50, article id 504002Article in journal (Refereed)
    Abstract [en]

    Biological membranes are continuously remodeled in the cell by specific membrane-shaping machineries to form, for example, tubes and vesicles. We examine fundamental mechanisms involved in the vesiculation processes induced by a cluster of envelope (E) and membrane (M) proteins of the dengue virus (DENV) using molecular dynamics simulations and a coarse-grained model. We show that an arrangement of three E-M heterotetramers (EM3) works as a bending unit and an ordered cluster of five such units generates a closed vesicle, reminiscent of the virus budding process. In silico mutagenesis of two charged residues of the anchor helices of the envelope proteins of DENV shows that Arg-471 and Arg-60 are fundamental to produce bending stress on the membrane. The fine-tuning between the size of the EM3 unit and its specific bending action suggests this protein unit is an important factor in determining the viral particle size.

  • 16.
    Elofsson, Arne
    et al.
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Solna, Sweden.
    Hess, Berk
    KTH Royal Inst Technol, Dept Phys, Swedish E Sci Res Ctr, Stockholm, Sweden.
    Lindahl, Erik
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, Solna, Sweden;KTH Royal Inst Technol, Dept Phys, Swedish E Sci Res Ctr, Stockholm, Sweden.
    Onufriev, Alexey
    Virginia Tech, Dept Comp Sci, Ctr Soft Matter & Biol Phys, Blacksburg, VA USA;Virginia Tech, Dept Phys, Ctr Soft Matter & Biol Phys, Blacksburg, VA USA.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Wallqvist, Anders
    US Army Med Res & Mat Command, Dept Def Biotechnol High Performance Comp Softwar, Telemed & Adv Technol Res Ctr, Ft Detrick, MD USA.
    Ten simple rules on how to create open access and reproducible molecular simulations of biological systems2019In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 15, no 1, article id e1006649Article in journal (Other academic)
  • 17.
    Fischer, Nina M.
    et al.
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Poleto, Marcelo D.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Uppsala University, Science for Life Laboratory, SciLifeLab. Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil .
    Steuer, Jakob
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology. Univ Konstanz, Dept Chem, Univ Str 10, D-78457 Constance, Germany.
    van der Spoel, David
    Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Influence of Na+ and Mg2+ ions on RNA structures studied with molecular dynamics simulations2018In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 46, no 10, p. 4872-4882Article in journal (Refereed)
    Abstract [en]

    The structure of ribonucleic acid (RNA) polymers is strongly dependent on the presence of, in particular Mg2+ cations to stabilize structural features. Only in high-resolution X-ray crystallography structures can ions be identified reliably. Here, we perform molecular dynamics simulations of 24 RNA structures with varying ion concentrations. Twelve of the structures were helical and the others complex folded. The aim of the study is to predict ion positions but also to evaluate the impact of different types of ions (Na+ or Mg2+) and the ionic strength on structural stability and variations of RNA. As a general conclusion Mg2+ is found to conserve the experimental structure better than Na+ and, where experimental ion positions are available, they can be reproduced with reasonable accuracy. If a large surplus of ions is present the added electrostatic screening makes prediction of binding-sites less reproducible. Distinct differences in ion-binding between helical and complex folded structures are found. The strength of binding (Delta G(+) for breaking RNA atom-ion interactions) is found to differ between roughly 10 and 26 kJ/mol for the different RNA atoms. Differences in stability between helical and complex folded structures and of the influence of metal ions on either are discussed.

  • 18.
    Fischer, Nina M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Ditz, Jonas C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Yildirim, Ahmet
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Properties of Organic Liquids when Simulated with Long-Range Lennard-Jones Interactions2015In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 11, no 7, p. 2938-2944Article in journal (Refereed)
    Abstract [en]

    In order to increase the accuracy of classical computer simulations, existing methodologies may need to be adapted. Hitherto, most force fields employ a truncated potential function to model van der Waals interactions, sometimes augmented with an analytical correction. Although such corrections are accurate for homogeneous systems with a long cutoff, they should not be used in inherently inhomogeneous systems such as biomolecular and interface systems. For such cases, a variant of the particle mesh Ewald algorithm (Lennard-Jones PME) was already proposed 20 years ago (Essmann et al. J. Chem. Phys. 1995, 103, 8577-8593), but it was implemented only recently (Wennberg et al. J. Chem. Thew), Comput 2013, 9, 3527 3537) in a major simulation code (GROMACS). The availability of this method allows surface tensions of liquids as well as bulk properties to be established, such as density and enthalpy of vaporization, without approximations due to truncation. Here, we report on simulations of,::150 liquids (taken from a force field benchmark: Caleman et al. J. Chem. Theory Comput. 2012, 8, 61-74) using three different force fields and compare simulations with and without explicit long-range van der Waals interactions. We find that the density and enthalpy of vaporization increase for most liquids using the generalized Amber force field (GAFF, Wang et al. J. Comput Chem. 2004, 25, 1157-1174) and the Charmm generalized force field (CGenFF, Vanommeslaeghe et al. J. Comput. Chem. 2010, 31, 671-690) but less so for OPLS/AA (Jorgensen and Tirado-Rives, Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 6665-6670), which was parametrized with an analytical correction to the van der Waals potential. The surface tension increases by approximate to 10(-2) N/m for all force fields. These results suggest that van der Waals attractions in force fields are too strong, in particular for the GAFF and CGenFF. In addition to the simulation results, we introduce a new version of a web server, http://virtualchemistry.org, aimed at facilitating sharing and reuse of input files for molecular simulations.

  • 19.
    Friemann, Rosmarie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Larsson, Daniel S. D.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Wang, Yaofeng
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Molecular Dynamics Simulations of a Membrane Protein-Micelle Complex in Vacuo2009In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, no 46, p. 16606-16607Article in journal (Refereed)
    Abstract [en]

    We report the first molecular dynamics simulations of an integral membrane protein in a detergent micelle under vacuum conditions. To mimic the dehydration process in electrospray ionization, the N-terminal outer membrane protein A transmembrane domain (OmpA171) from Escherichia coli embedded in a dodecylphosphocholine (DPC) detergent micelle has been simulated with water shells of varying thickness. Removal of the water molecules leaves the membrane protein relatively unaffected by the vacuum conditions. The major structural change occurs in the surrounding micelle, where the DPC molecules structurally rearrange from a normal-phase micelle with DPC detergents radiating spherically from OmpA171 to a structure where the DPC molecules form a layered onion structure in which the head groups, which strive to interact with each other, form an intermediate layer between the inner layer of tail groups that are expelled to the surface, protruding into the void.

  • 20. Gaffney, K J
    et al.
    Lindenberg, A M
    Larsson, J
    Sokolowski-Tinten, K
    Blome, C
    Synnergren, O
    Sheppard, J
    Caleman, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    MacPhee, A G
    Weinstein, D
    Lowney, D P
    Allison, T
    Matthews, T
    Falcone, R W
    Cavalieri, A L
    Fritz, D M
    Lee, S H
    Bucksbaum, P H
    Reis, D A
    Rudati, J
    Macrander, A T
    Fuoss, P H
    Kao, C C
    Siddons, D P
    Pahl, R
    Moffat, K
    Als-Nielsen, J
    Duesterer, S
    Ischebeck, R
    Schlarb, H
    Schulte-Schrepping, H
    Schneider, J
    von der Linde, D
    Hignette, O
    Sette, F
    Chapman, H N
    Lee, R W
    Hansen, T N
    Wark, J S
    Bergh, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    Huldt, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    van der Spoel, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    Timneanu, N
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    Hajdu, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molecular Biophysics.
    Akre, R A
    Bong, E
    Krejcik, P
    Arthur, J
    Brennan, S
    Luening, K
    Hastings, J B
    Observation of structural anisotropy and the onset of liquidlike motion during the nonthermal melting of InSb.2005In: Phys Rev Lett, ISSN 0031-9007, Vol. 95, no 12, p. 125701-Article in journal (Other scientific)
  • 21.
    Ghahremanpour, Mohammad M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics. DESY, Ctr Free Electron Laser Sci, DE-22607 Hamburg, Germany.
    Hutchison, Geoffrey R.
    Univ Pittsburgh, Dept Chem, Pittsburgh, PA 15260 USA.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Polarizable Drude Model with s-Type Gaussian or Slater Charge Density for General Molecular Mechanics Force Fields2018In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 14, no 11, p. 5553-5566Article in journal (Refereed)
    Abstract [en]

    Gas-phase electric properties of molecules can be computed routinely using wave function methods or density functional theory (DFT). However, these methods remain computationally expensive for high-throughput screening of the vast chemical space of virtual compounds. Therefore, empirical force fields are a more practical choice in many cases, particularly since force field methods allow one to routinely predict the physicochemical properties in the condensed phases. This work presents Drude polarizable models, to increase the physical realism in empirical force fields, where the core particle is treated as a point charge and the Drude particle is treated either as a 1s-Gaussian or a ns-Slater (n = 1, 2, 3) charge density. Systematic parametrization to large high-quality quantum chemistry data obtained from the open access Alexandria Library (https://doi.org/10.5281/zenodo.1004711) ensures the transferability of these parameters. The dipole moments and isotropic polarizabilities of the isolated molecules predicted by the proposed Drude models are in agreement with experiment with accuracy similar to DFT calculations at the B3LYP/aug-cc-pVTZ level of theory. The results show that the inclusion of explicit polarization into the models reduces the root-mean-square deviation with respect to DFT calculations of the predicted dipole moments of 152 dimers and clusters by more than 50%. Finally, we show that the accuracy of the electrostatic interaction energy of the water dimers can be improved systematically by the introduction of polarizable smeared charges as a model for charge penetration.

  • 22.
    Ghahremanpour, Mohammad M.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Van Der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Uppsala University, Science for Life Laboratory, SciLifeLab.
    The Alexandria library, a quantum-chemical database of molecular properties for force field development2018In: Scientific Data, E-ISSN 2052-4463, Vol. 5, article id 180062Article in journal (Refereed)
    Abstract [en]

    Data quality as well as library size are crucial issues for force field development. In order to predict molecular properties in a large chemical space, the foundation to build force fields on needs to encompass a large variety of chemical compounds. The tabulated molecular physicochemical properties also need to be accurate. Due to the limited transparency in data used for development of existing force fields it is hard to establish data quality and reusability is low. This paper presents the Alexandria library as an open and freely accessible database of optimized molecular geometries, frequencies, electrostatic moments up to the hexadecupole, electrostatic potential, polarizabilities, and thermochemistry, obtained from quantum chemistry calculations for 2704 compounds. Values are tabulated and where available compared to experimental data. This library can assist systematic development and training of empirical force fields for a broad range of molecules.

  • 23. Ghahremanpour, Mohammad Mehdi
    et al.
    Arab, Seyed Shahriar
    Aghazadeh, Saman Biook
    Zhang, Jin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    MemBuilder: a web-based graphical interface to build heterogeneously mixed membrane bilayers for the GROMACS biomolecular simulation program2014In: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 30, no 3, p. 439-441Article in journal (Refereed)
    Abstract [en]

    Motivation: Molecular dynamics (MD) simulations have had a profound impact on studies of membrane proteins during past two decades, but the accuracy of MD simulations of membranes is limited by the quality of membrane models and the applied force fields. Membrane models used in MD simulations mostly contain one kind of lipid molecule. This is far from reality, for biological membranes always contain more than one kind of lipid molecule. Moreover, the lipid composition and their distribution are functionally important. As a result, there is a necessity to prepare more realistic lipid membranes containing different types of lipids at physiological concentrations. Results: To automate and simplify the building process of heterogeneous lipid bilayers as well as providing molecular topologies for included lipids based on both united and all-atom force fields, we provided MemBuilder as a web-based graphical user interface.

  • 24.
    Ghahremanpour, Mohammad Mehdi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Caleman, C
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Hutchison, Geoffrey R.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Polarizable Drude Model with s‑Type Gaussian or Slater Charge Density for General Molecular Mechanics Force Fields2018In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626Article in journal (Refereed)
  • 25.
    Ghahremanpour, Mohammad Mehdi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Ditz, Jonas C.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Lindh, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Theoretical Chemistry.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Large-scale calculations of gas phase thermochemistry: Enthalpy of formation, standard entropy, and heat capacity2016In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 145Article in journal (Refereed)
  • 26.
    Ghahremanpour, Mohammad Mehdi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Efficient Physics-Based Polarizable Charges: from Organic Compounds to ProteinsManuscript (preprint) (Other academic)
  • 27.
    Ghahremanpour, Mohammad Mehdi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van Maaren, Paul J
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    The Alexandria library, a quantum-chemical database of molecular properties for force field development2018In: Scientific Data, E-ISSN 2052-4463Article in journal (Refereed)
  • 28.
    Hajdu, J
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Hodgson, K
    Miao, J
    van der Spoel, D
    Neutze, R
    Robinson, C. V
    Faigel, G
    Jacobsen, C
    Kirz, J
    Sayre, D
    Weckert, E
    Materlik, G
    Szöke, A
    Structural studies on single particles and biomolecules. LCLS: The First Experiments.2000Other (Other scientific)
  • 29.
    Hajdu, J.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Neutze, R
    Wouts, R
    van der Spoel, D
    Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Ultrafast Structural Studies on Biological Molecules by X-Rays.1999In: AIP Conference proceedings, 1999, p. 377-385Conference paper (Other scientific)
  • 30. Hess, Berk
    et al.
    Kutzner, Carsten
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Lindahl, Erik
    GROMACS 4: Algorithms for highly efficient, load-balanced, and scalable molecular simulation2008In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 4, no 3, p. 435-447Article in journal (Refereed)
    Abstract [en]

    Molecular simulation is an extremely useful, but computationally very expensive tool for studies of chemical and biomolecular systems. Here, we present a new implementation of our molecular simulation toolkit GROMACS which now both achieves extremely high performance on single processors from algorithmic optimizations and hand-coded routines and simultaneously scales very well on parallel machines. The code encompasses a minimal-communication domain decomposition algorithm, full dynamic load balancing, a state-of-the-art parallel constraint solver, and efficient virtual site algorithms that allow removal of hydrogen atom degrees of freedom to enable integration time steps up to 5 fs; for atomistic simulations also in parallel. To improve the scaling properties of the common particle mesh Ewald electrostatics algorithms, we have in addition used a Multiple-Program, Multiple-Data approach, with separate node domains responsible for direct and reciprocal space interactions. Not only does this combination of algorithms enable extremely long simulations of large systems but also it provides that simulation performance on quite modest numbers of standard cluster nodes.

  • 31.
    Hetenyi, C
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    van der Spoel, D
    Earth Sciences, Department of Earth Sciences.
    Efficient docking of peptides to proteins without prior knowledge of the binding site2002In: PROTEIN SCIENCE, Vol. 11, p. 1729-1737Article in journal (Refereed)
  • 32. Hetenyi, Csaba
    et al.
    van der Spoel, David
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Blind docking of drug-sized compounds to proteins with up to a thousand residues.2006In: FEBS Lett, ISSN 0014-5793, Vol. 580, no 5, p. 1447-50Article in journal (Other scientific)
  • 33.
    Hub, Jochen
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Caleman, Carl
    Center for Free-Electron Laser Science, DESY, Notkestraße 85,.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Organic molecules on the surface of water droplets: an energetic perspective2012In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 14, no 27, p. 9537-9545Article in journal (Refereed)
    Abstract [en]

    The solubility of organic molecules is a well established property, founded on decades of measurements, the results of which have been tabulated in handbooks. Under atmospheric conditions water droplets may form containing small amounts of other molecules. Such droplets typically have a very large area to volume ratio, which may shift the solvation equilibrium towards molecules residing on the droplet surface. The presence of organic molecules on droplet surfaces is extremely important for reactivity – it is well established that certain chemical reactions are more prevalent under atmospheric conditions than in bulk. Here we present a thermodynamic rationalization of the surface solvation properties of methanol, ethanol, propanoic acid, n-butylamine, diethyl ether, and neopentane based on potential of mean force (PMF) calculations – we have previously demonstrated that an energetic description is a very powerful means of disentangling the factors governing solvation (Caleman et al., Proc. Natl. Acad. Sci. U. S. A., 2011, 108, 6838–6842). All organic molecules investigated here are preferentially solvated on the surface of the droplets rather than in the inside, yet the magnitude of surface preference may differ by orders of magnitude. In order to dissect the energetic contributions that govern surface preference, we decompose the PMF into enthalpic and entropic components, and, in a second step, into contributions from water–water and solute–water interactions. The analysis demonstrates that surface preference is primarily an enthalpic effect, but the magnitude of surface preference of solutes containing large apolar groups is enhanced due to entropy. We introduce an analysis of the droplet PMFs that allows one to extrapolate the results to larger droplets. From this we can estimate the solubility of the solutes in water droplets, demonstrating that the solubility in droplets can be orders of magnitude larger than in bulk water. Our findings have implications for understanding the process of electrospray ionization, an important technique in biological mass spectrometry, since our work strongly suggests that in equilibrium biomolecules would be adsorbed on the droplet surface as well.

  • 34. Hub, Jochen S.
    et al.
    Wolf, Maarten G.
    Caleman, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    van Maaren, Paul J.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Groenhof, Gerrit
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Thermodynamics of hydronium and hydroxide surface solvation2014In: Chemical Science, ISSN 2041-6520, Vol. 5, no 5, p. 1745-1749Article in journal (Refereed)
    Abstract [en]

    The concentration of hydronium and hydroxide at the water-air interface has been debated for a long time. Recent evidence from a range of experiments and theoretical calculations strongly suggests the water surface to be somewhat acidic. Using novel polarizable models we have performed potential of mean force calculations of a hydronium ion, a hydroxide ion and a water molecule in a water droplet and a water slab and we were able to rationalize that hydronium, but not hydroxide, is slightly enriched at the surface for two reasons. First, because the hydrogen bond acceptance capacity of hydronium is weaker than water and it is more favorable to have the hydronium oxygen on the surface. Second, hydroxide ions are expelled from the surface of the droplets, due to the entropy being lower when a hydroxide ion is hydrated on the surface. As a result, the water dissociation constant pK(w) increases slightly near the surface. The results are corroborated by calculations of surface tension of NaOH solutions that are in reasonable agreement with the experiment. The structural and thermodynamic interpretation of hydronium and hydroxide hydration provided by these calculations opens the route to a better understanding of atmospheric and surface chemistry.

  • 35.
    Jeszenoi, Norbert
    et al.
    Eotvos Lorand Univ, Dept Genet, Pazmany Peter Setany 1-C, H-1117 Budapest, Hungary.;Univ Pecs, Ctr Neurosci, Szentagothai Res Ctr, MTA NAP B Mol Neuroendocrinol Grp,Inst Physiol, Szigeti Ut 12, H-7624 Pecs, Hungary..
    Balint, Monika
    Eotvos Lorand Univ, Dept Biochem, Pazmany Peter Setany 1-C, H-1117 Budapest, Hungary..
    Horvath, Istvan
    Univ Szeged, Chem Doctoral Sch, Dugon Ter 13, H-6720 Szeged, Hungary..
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Hetenyi, Csaba
    Hungarian Acad Sci, MTA ELTE Mol Biophys Res Grp, Pazmany Setany 1-C, H-1117 Budapest, Hungary..
    Exploration of Interfacial Hydration Networks of Target Ligand Complexes2016In: Journal of Chemical Information and Modeling, ISSN 1549-9596, E-ISSN 1549-960X, Vol. 56, no 1, p. 148-158Article in journal (Refereed)
    Abstract [en]

    Interfacial hydration strongly influences interactions between biomolecules. For example, drug target complexes are often stabilized by hydration networks formed between hydrophilic residues and water molecules at the interface. Exhaustive exploration of hydration networks is, challenging for experimental as well as theoretical methods due to high mobility of participating water molecules. In the present study, we introduced a tool for determination of the complete, void-free hydration structures of molecular interfaces. The tool was applied to 31 complexes including histone proteins, a HIV-1 protease, a G-protein-signaling modulator, and peptide ligands of various lengths. The complexes contained 344 experimentally determined water positions used for validation, and excellent agreement with these was obtained. High-level cooperation between interfacial water molecules was detected by a new approach based on the decomposition of hydration networks into static and dynamic network regions (subnets). Besides providing hydration structures at the atomic level, our results uncovered hitherto hidden networking fundaments of integrity and stability of complex biomolecular interfaces filling an important gap in the toolkit of drug design and structural biochemistry. The presence of continuous, static regions of the interfacial hydration network was found necessary also for stable complexes of histone proteins participating in chromatin assembly and epigenetic regulation.

  • 36. Jeszenoi, Norbert
    et al.
    Horvath, Istvan
    Balint, Monika
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Hetenyi, Csaba
    Mobility-based prediction of hydration structures of protein surfaces2015In: Bioinformatics, ISSN 1367-4803, E-ISSN 1367-4811, Vol. 31, no 12, p. 1959-1965Article in journal (Refereed)
    Abstract [en]

    Motivation: Hydration largely determines solubility, aggregation of proteins and influences interactions between proteins and drug molecules. Despite the importance of hydration, structural determination of hydration structure of protein surfaces is still challenging from both experimental and theoretical viewpoints. The precision of experimental measurements is often affected by fluctuations and mobility of water molecules resulting in uncertain assignment of water positions. Results: Our method can utilize mobility as an information source for the prediction of hydration structure. The necessary information can be produced by molecular dynamics simulations accounting for all atomic interactions including water-water contacts. The predictions were validated and tested by comparison to more than 1500 crystallographic water positions in 20 hydrated protein molecules including enzymes of biomedical importance such as cyclin-dependent kinase 2. The agreement with experimental water positions was larger than 80% on average. The predictions can be particularly useful in situations where no or limited experimental knowledge is available on hydration structures of molecular surfaces.

  • 37. Kutzner, Carsten
    et al.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Fechner, Martin
    Lindahl, Erik
    Schmitt, Udo W.
    de Groot, Bert L.
    Grubmüller, Helmut
    Speeding up parallel GROMACS on high-latency networks2007In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 28, no 12, p. 2075-2084Article in journal (Refereed)
    Abstract [en]

    We investigate the parallel scaling of the GROMACS molecular dynamics code on Ethernet Beowulf clusters and what prerequisites are necessary for decent scaling even on such clusters with only limited bandwidth and high latency. GROMACS 3.3 scales well on supercomputers like the IBM p690 (Regatta) and on Linux clusters with a special interconnect like Myrinet or Infiniband. Because of the high single-node performance of GROMACS, however, on the widely used Ethernet switched clusters, the scaling typically breaks down when more than two computer nodes are involved, limiting the absolute speedup that can be gained to about 3 relative to a single-CPU run. With the LAM MPI implementation, the main scaling bottleneck is here identified to be the all-to-all communication which is required every time step. During such an all-to-all communication step, a huge amount of messages floods the network, and as a result many TCP packets are lost. We show that Ethernet flow control prevents network congestion and leads to substantial scaling improvements. For 16 CPUs, e.g., a speedup of 11 has been achieved. However, for more nodes this mechanism also fails. Having optimized an all-to-all routine, which sends the data in an ordered fashion, we show that it is possible to completely prevent packet loss for any number of multi-CPU nodes. Thus, the GROMACS scaling dramatically improves, even for switches that lack flow control. In addition, for the common HP ProCurve 2848 switch we find that for optimum all-to-all performance it is essential how the nodes are connected to the switch's ports. This is also demonstrated for the example of the Car-Parinello MD code.

  • 38.
    Larsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Liljas, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Structure and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Virus Capsid Dissolution Studied by Microsecond Molecular Dynamics Simulations2012In: PloS Computational Biology, ISSN 1553-734X, E-ISSN 1553-7358, Vol. 8, no 5, p. e1002502-Article in journal (Refereed)
    Abstract [en]

    Dissolution of many plant viruses is thought to start with swelling of the capsid caused by calcium removal following infection, but no high-resolution structures of swollen capsids exist. Here we have used microsecond all-atom molecular simulations to describe the dynamics of the capsid of satellite tobacco necrosis virus with and without the 92 structural calcium ions. The capsid expanded 2.5% upon removal of the calcium, in good agreement with experimental estimates. The water permeability of the native capsid was similar to that of a phospholipid membrane, but the permeability increased 10-fold after removing the calcium, predominantly between the 2-fold and 3-fold related subunits. The two calcium binding sites close to the icosahedral 3-fold symmetry axis were pivotal in the expansion and capsid-opening process, while the binding site on the 5-fold axis changed little structurally. These findings suggest that the dissociation of the capsid is initiated at the 3-fold axis.

  • 39.
    Larsson, Daniel
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Screening for the Location of RNA Using the Chloride Ion Distribution in Simulations of Virus Capsids2012In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 8, no 7, p. 2474-2483Article in journal (Refereed)
    Abstract [en]

    The complete structure of the genomic material inside a virus capsid remains elusive, although a limited amount of symmetric nucleic acid can be resolved in the crystal structure of 17 icosahedral viruses. The negatively charged sugar-phosphate backbone of RNA and DNA as well as the large positive charge of the interior surface of the virus capsids suggest that electrostatic complementarity is an important factor in the packaging of the genomes in these viruses. To test how much packing information is encoded by the electrostatic and steric envelope of the capsid interior, we performed extensive all-atom molecular dynamics (MD) simulations of virus capsids with explicit water molecules and solvent ions. The model systems were two small plant viruses in which significant amounts of RNA has been observed by X-ray crystallography: satellite tobacco mosaic virus (STMV, 62% RNA visible) and satellite tobacco necrosis virus (STNV, 34% RNA visible). Simulations of half-capsids of these viruses with no RNA present revealed that the binding sites of RNA correlated well with regions populated by chloride ions, suggesting that it is possible to screen for the binding sites of nucleic acids by determining the equilibrium distribution of negative ions. By including the crystallographically resolved RNA in addition to ions, we predicted the localization of the unresolved RNA in the viruses. Both viruses showed a hot-spot for RNA binding at the S-fold symmetry axis. The MD simulations were compared to predictions of the chloride density based on nonlinear Poisson-Boltzmann equation (PBE) calculations with mobile ions. Although the predictions are superficially similar, the PBE calculations overestimate the ion concentration close to the capsid surface and underestimate it far away, mainly because protein dynamics is not taken into account. Density maps from chloride screening can be used to aid in building atomic models of packaged virus genomes. Knowledge of the principles of genome packaging might be exploited for both antiviral therapy and technological applications.

  • 40.
    Lehmann, Laura C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Hewitt, Graeme
    Francis Crick Inst, 1 Midland Rd, London NW1 1AT, England..
    Aibara, Shintaro
    Stockholm Univ, Dept Biochem & Biophys, Sci Life Lab, S-17165 Solna, Sweden..
    Leitner, Alexander
    Swiss Fed Inst Technol, Inst Mol Syst Biol, Dept Biol, CH-8093 Zurich, Switzerland..
    Marklund, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Maslen, Sarah L.
    MRC Lab Mol Biol, Francis Crick Ave,Cambridge Biomed Campus, Cambridge CB2 0QH, England..
    Maturi, Varun
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Chen, Yang
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics.
    Skehel, J. Mark
    MRC Lab Mol Biol, Francis Crick Ave,Cambridge Biomed Campus, Cambridge CB2 0QH, England..
    Moustakas, Aristidis
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm, Ludwig Institute for Cancer Research. Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Boulton, Simon J.
    Francis Crick Inst, 1 Midland Rd, London NW1 1AT, England..
    Deindl, Sebastian
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular Systems Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Mechanistic Insights into Autoinhibition of the Oncogenic Chromatin Remodeler ALC12017In: Molecular Cell, ISSN 1097-2765, E-ISSN 1097-4164, Vol. 68, no 5, p. 847-859.e7Article in journal (Refereed)
    Abstract [en]

    Human ALC1 is an oncogene-encoded chromatin-remodeling enzyme required for DNA repair that possesses a poly(ADP-ribose) (PAR)-binding macro domain. Its engagement with PARylated PARP1 activates ALC1 at sites of DNA damage, but the underlying-mechanism remains unclear. Here, we establish a dual role for the macro domain in autoinhibition of ALC1 ATPase activity and coupling to nucleosome mobilization. In the absence of DNA damage, an inactive conformation of the ATPase is maintained by juxtaposition of the macro domain against predominantly the C-terminal ATPase lobe through conserved electrostatic interactions. Mutations within this interface displace the macro domain, constitutively activate the ALC1 ATPase independent of PARylated PARP1, and alter the dynamics of ALC1 recruitment at DNA damage sites. Upon DNA damage, binding of PARylated PARP1 by the macro domain induces a conformational change that relieves autoinhibitory interactions with the ATPase motor, which selectively activates ALC1 remodeling upon recruitment to sites of DNA damage.

  • 41. Lemkul, Justin A.
    et al.
    Roux, Benoit
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    MacKerell, Alexander D., Jr.
    Implementation of Extended Lagrangian Dynamics in GROMACS for Polarizable Simulations Using the Classical Drude Oscillator Model2015In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 36, no 19, p. 1473-1479Article in journal (Refereed)
    Abstract [en]

    Explicit treatment of electronic polarization in empirical force fields used for molecular dynamics simulations represents an important advancement in simulation methodology. A straightforward means of treating electronic polarization in these simulations is the inclusion of Drude oscillators, which are auxiliary, charge-carrying particles bonded to the cores of atoms in the system. The additional degrees of freedom make these simulations more computationally expensive relative to simulations using traditional fixed-charge (additive) force fields. Thus, efficient tools are needed for conducting these simulations. Here, we present the implementation of highly scalable algorithms in the GROMACS simulation package that allow for the simulation of polarizable systems using extended Lagrangian dynamics with a dual Nose-Hoover thermostat as well as simulations using a full self-consistent field treatment of polarization. The performance of systems of varying size is evaluated, showing that the present code parallelizes efficiently and is the fastest implementation of the extended Lagrangian methods currently available for simulations using the Drude polarizable force field.

  • 42.
    Lindahl, E
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Hess, B
    van der Spoel, D
    Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    GROMACS 3.0: a package for molecular simulation and trajectory analysis2001In: JOURNAL OF MOLECULAR MODELING, ISSN 0948-5023, Vol. 7, no 8, p. 306-317Article in journal (Refereed)
    Abstract [en]

    GROMACS 3.0 is the latest release of a versatile and very well optimized package for molecular simulation. Much effort has been devoted to achieving extremely high performance on both workstations and parallel computers. The design includes an extraction

  • 43. Lindenberg, A M
    et al.
    Larsson, J
    Sokolowski-Tinten, K
    Gaffney, K J
    Blome, C
    Synnergren, O
    Sheppard, J
    Caleman, C
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Macphee, A G
    Weinstein, D
    Lowney, D P
    Allison, T K
    Matthews, T
    Falcone, R W
    Cavalieri, A L
    Fritz, D M
    Lee, S H
    Bucksbaum, P H
    Reis, D A
    Rudati, J
    Fuoss, P H
    Kao, C C
    Siddons, D P
    Pahl, R
    Als-Nielsen, J
    Duesterer, S
    Ischebeck, R
    Schlarb, H
    Schulte-Schrepping, H
    Tschentscher, Th
    Schneider, J
    von der Linde, D
    Hignette, O
    Sette, F
    Chapman, H N
    Lee, R W
    Hansen, T N
    Techert, S
    Wark, J S
    Bergh, M
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Huldt, G
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    van der Spoel, D
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Timneanu, N
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Hajdu, J
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology. Molekylär biofysik.
    Akre, R A
    Bong, E
    Krejcik, P
    Arthur, J
    Brennan, S
    Luening, K
    Hastings, J B
    Atomic-scale visualization of inertial dynamics.2005In: Science, ISSN 1095-9203, Vol. 308, no 5720, p. 392-5Article in journal (Refereed)
    Abstract [en]

    The motion of atoms on interatomic potential energy surfaces is fundamental to the dynamics of liquids and solids. An accelerator-based source of femtosecond x-ray pulses allowed us to follow directly atomic displacements on an optically modified energy landscape, leading eventually to the transition from crystalline solid to disordered liquid. We show that, to first order in time, the dynamics are inertial, and we place constraints on the shape and curvature of the transition-state potential energy surface. Our measurements point toward analogies between this nonequilibrium phase transition and the short-time dynamics intrinsic to equilibrium liquids.

  • 44. Lourenco, Tuanan C.
    et al.
    Coelho, Mariny F. C.
    Ramalho, Teodorico C.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Costa, Luciano T.
    Insights on the Solubility of CO2 in 1-Ethyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide from the Microscopic Point of View2013In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, no 13, p. 7421-7429Article in journal (Refereed)
    Abstract [en]

    Emissions of greenhouse gases due to human activities have been well documented as well as the effects on global warming resulting from it. Efforts to reduce greenhouse gases at the source are crucial to curb climate change, but due to insignificant economic incentives to reduce usage of fossil fuels, not a lot of progress has been made by this route. This necessitates additional measures to reduce the occurrence of greenhouse gases in the atmosphere. Here we used theoretical methods to study the solubility of carbon dioxide in ionic liquids (ILs) since sequestration of CO2 in ILs has been proposed as a possible technology for reducing the emissions of CO2 to the atmosphere. Ionic liquids form a class of solvents with melting temperatures below 100 degrees C and, due to very low vapor pressures, which are not volatile. We have performed molecular dynamics (MD) simulations of 1-ethyl-3-methylimidazolium (C(2)mim) bis(trifluoromethylsulfonyl)imide (Tf2N) and its mixtures with carbon dioxide in order to investigate the CO2 concentration effect on the CO2-cation and CO2-anion interactions. A systematic investigation of CO2 concentration effects on resulting equilibrium liquid structure, and the local environment of the ions is provided The Quantum Theory of Atoms in Molecules (QTAIM) was used to determine the interaction energy for CO2-cation and CO2-anion complexes from uncorrelated structures derived from MD simulations. A spatial distribution function analysis demonstrates the specific interactions between CO2 and the ionic liquid. Our findings indicate that the total volume of the system increases with the CO2 concentration, with a molar volume of CO2 of about 0.038 L/mol, corresponding to liquid CO2 under a pressure of 100 bar. In other words, the IL effectively pressurizes the CO2 inside its matrix. The thermodynamics of CO2 solvation in C2 min-Tf2N were computed using free energy techniques, and the solubility of CO2 is found to be higher in this IL (-3.7 +/- 1 kcal/mol) than in water (+0.2 kJ/mol), predominantly due to anion-CO2 interactions.

  • 45. Lundborg, Magnus
    et al.
    Apostolov, Rossen
    Spångberg, Daniel
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Gardenäs, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Lindahl, Erik
    An Efficient and Extensible Format, Library, and API for Binary Trajectory Data from Molecular Simulations2014In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 35, no 3, p. 260-269Article in journal (Refereed)
    Abstract [en]

    Molecular dynamics simulations is an important application in theoretical chemistry, and with the large high-performance computing resources available today the programs also generate huge amounts of output data. In particular in life sciences, with complex biomolecules such as proteins, simulation projects regularly deal with several terabytes of data. Apart from the need for more cost-efficient storage, it is increasingly important to be able to archive data, secure the integrity against disk or file transfer errors, to provide rapid access, and facilitate exchange of data through open interfaces. There is already a whole range of different formats used, but few if any of them (including our previous ones) fulfill all these goals. To address these shortcomings, we present Trajectory Next Generation (TNG)a flexible but highly optimized and efficient file format designed with interoperability in mind. TNG both provides state-of-the-art multiframe compression as well as a container framework that will make it possible to extend it with new compression algorithms without modifications in programs using it. TNG will be the new file format in the next major release of the GROMACS package, but it has been implemented as a separate library and API with liberal licensing to enable wide adoption both in academic and commercial codes. 

  • 46.
    Maia, Filipe R. N. C.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Ekeberg, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Timneanu, Nicusor
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Hajdu, Janos
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Molecular biophysics.
    Structural variability and the incoherent addition of scattered intensities in single-particle diffraction2009In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 80, no 3, p. 031905-Article in journal (Refereed)
    Abstract [en]

    X-ray lasers may allow structural studies on single particles and biomolecules without crystalline periodicity in the samples. We examine here the effect of sample dynamics as a source of structural heterogeneity on the resolution of the reconstructed image of a small protein molecule. Structures from molecular-dynamics simulations of lysozyme were sampled and aligned. These structures were then used to calculate diffraction patterns corresponding to different dynamic states. The patterns were incoherently summed and the resulting data set was phased using the oversampling method. Reconstructed images of hydrated and dehydrated lysozyme gave resolutions of 3.7 angstrom and 7.6 angstrom, respectively. These are significantly worse than the root-mean-square deviation of the hydrated (2.7 angstrom for all atoms and 1.45 angstrom for C-alpha positions) or dehydrated (3.7 angstrom for all atoms and 2.5 angstrom for C-alpha positions) structures. The noise introduced by structural dynamics and incoherent addition of dissimilar structures restricts the maximum resolution to be expected from direct image reconstruction of dynamic systems. A way of potentially reducing this effect is by grouping dynamic structures into distinct structural substates and solving them separately.

  • 47.
    Maia, Filipe
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Szoke, Abraham
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    DeLano, Warren
    van der Spoel, David
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Faculty of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Interactive visualization of electron density slices2005In: J. Appl. Cryst., ISSN 0021-8898, Vol. 38, p. 563-565Article in journal (Other (popular scientific, debate etc.))
    Abstract [en]

    A new tool has been developed to aid in the visualization of electron density in crystals or from quantum chemistry calculations. It displays the fine details of the electron density on a plane and the three-dimensional model of the molecule at the same time. The program enables the user to examine the details of weak or irregular features. Such features frequently occur in low-resolution maps, where they determine the correct tracing of a protein backbone. In high-resolution maps, solvent regions are difficult or impossible to observe using isosurfaces. The tool has been integrated into an existing molecular visualization package (PyMol) making it possible to observe and interact both with a structure model and the electron density slices freely, simultaneously and independently. This visualization model fills a gap in the visualization methods available to crystallographers and others who work with electron density maps.

  • 48.
    Manzetti, Sergio
    et al.
    FJORDFORSK Hlth & Environm Sci, N-5743 Flam, Norway.
    Behzadi, Hadi
    Tarbiat Moallem Univ, Dept Chem, Tehran, Iran.
    Otto, Andersen
    Western Norway Res Inst, N-6851 Sogndal, Norway.
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational and Systems Biology.
    Fullerenes toxicity and electronic properties2013In: Environmental Chemistry Letters, ISSN 1610-3653, E-ISSN 1610-3661, Vol. 11, no 2, p. 105-118Article, review/survey (Refereed)
    Abstract [en]

    Nanotechnology globally represents a new direction within scientific development, where the atomic and electronic properties of molecules are used in a unique fashion to produce and construct new and exotic materials and products. Fullerenes (Bucky balls, C-60) constitute a particular group within the field of nanotechnology. Fullerenes find applications in medicine, industrial chemistry and electronics. However, there are several unanswered questions about fullerenes and their toxicological properties. Most toxicological studies on fullerenes evolve around the in vitro and in vivo aspects of pristine C-60 along with chemically modified C-60 molecules. We reviewed toxicology reports on C-60. We bring a critical and challenging evaluation of the electronic and quantum properties of C-60 molecules in context with the implications on cellular factors and metabolites. The evaluation shows that the reactivity and quantum chemical properties of C-60 can have unexpected effects in the cell, by principally absorbing metabolites, such as OH- and H+ ions and alter its reactivity. We thus challenge the present view of C-60 solely based on empirical studies, based on the electronic properties of C-60 that vary considerably with their size and reaction path. A further example of this is the absorption of divalent zinc ions, which shows an increase in reactivity of the C-60 that presents an important pattern of chemical state, reactivity and toxicological potential. The results evaluate the toxicological potential of C-60 from a different angle than conventional, by applying a blend of critical review of the findings on C-60 toxicity, their chemical and electronic properties.

  • 49.
    Manzetti, Sergio
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    McCulloch, Daniel R
    Herington, Adrian C.
    Van Der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Molecular dynamics of MMP-3, ADAM-9 and ADAM-10 in complex with hypothetical substrates: New implications for catalysis and substrate affinity2003In: Journal of Computer-Aided Molecular Design, ISSN 0920-654X, E-ISSN 1573-4951, Vol. 17, no 9, p. 551-565Article in journal (Other academic)
  • 50.
    Manzetti, Sergio
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Computational Biology and Bioinformatics. Fjordforsk AS Inst Sci & Technol, N-6894 Midtun, Vangsnes, Norway..
    van der Spoel, David
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology.
    Impact of sludge deposition on biodiversity2015In: Ecotoxicology, ISSN 0963-9292, E-ISSN 1573-3017, Vol. 24, no 9, p. 1799-1814Article, review/survey (Refereed)
    Abstract [en]

    Sludge deposition in the environment is carried out in several countries. It encompasses the dispersion of treated or untreated sludge in forests, marsh lands, open waters as well as estuarine systems resulting in the gradual accumulation of toxins and persistent organic compounds in the environment. Studies on the life cycle of compounds from sludge deposition and the consequences of deposition are few. Most reports focus rather on treatment-methods and approaches, legislative aspects as well as analytical evaluations of the chemical profiles of sludge. This paper reviews recent as well as some older studies on sludge deposition in forests and other ecosystems. From the literature covered it can be concluded that sludge deposition induces two detrimental effects on the environment: (1) raising of the levels of persistent toxins in soil, vegetation and wild life and (2) slow and long-termed biodiversity-reduction through the fertilizing nutrient pollution operating on the vegetation. Since recent studies show that eutrophication of the environment is a major threat to global biodiversity supplying additional nutrients through sludge-based fertilization seems imprudent. Toxins that accumulate in the vegetation are transferred to feeding herbivores and their predators, resulting in a reduced long-term survival chance of exposed species. We briefly review current legislation for sludge deposition and suggest alternative routes to handling this difficult class of waste.

123 1 - 50 of 113
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf