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Mandl, Thomas
Publications (5 of 5) Show all publications
Kierspel, T., Kadek, A., Barran, P., Bellina, B., Bijedic N, A., Brodmerkel, M. N., . . . Uetrecht, C. (2023). Coherent diffractive imaging of proteins and viral capsids: simulating MS SPIDOC. Analytical and Bioanalytical Chemistry, 415(18 SI), 4209-4220
Open this publication in new window or tab >>Coherent diffractive imaging of proteins and viral capsids: simulating MS SPIDOC
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2023 (English)In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 415, no 18 SI, p. 4209-4220Article in journal (Refereed) Published
Abstract [en]

MS SPIDOC is a novel sample delivery system designed for single (isolated) particle imaging at X-ray Free-Electron Lasers that is adaptable towards most large-scale facility beamlines. Biological samples can range from small proteins to MDa particles. Following nano-electrospray ionization, ionic samples can be m/z-filtered and structurally separated before being oriented at the interaction zone. Here, we present the simulation package developed alongside this prototype. The first part describes how the front-to-end ion trajectory simulations have been conducted. Highlighted is a quadrant lens; a simple but efficient device that steers the ion beam within the vicinity of the strong DC orientation field in the interaction zone to ensure spatial overlap with the X-rays. The second part focuses on protein orientation and discusses its potential with respect to diffractive imaging methods. Last, coherent diffractive imaging of prototypical T = 1 and T = 3 norovirus capsids is shown. We use realistic experimental parameters from the SPB/SFX instrument at the European XFEL to demonstrate that low-resolution diffractive imaging data (q < 0.3 nm−1) can be collected with only a few X-ray pulses. Such low-resolution data are sufficient to distinguish between both symmetries of the capsids, allowing to probe low abundant species in a beam if MS SPIDOC is used as sample delivery.

Place, publisher, year, edition, pages
Springer Nature, 2023
Keywords
SPI, X-ray, Native MS, Protein complex structure, Viral particles, Simulation, Modeling
National Category
Biophysics
Identifiers
urn:nbn:se:uu:diva-500359 (URN)10.1007/s00216-023-04658-y (DOI)000963181300001 ()37014373 (PubMedID)
Funder
Swedish Research Council, 2018-00740Swedish Research Council, 2020-04825EU, Horizon 2020, 801406
Available from: 2023-04-14 Created: 2023-04-14 Last updated: 2024-01-26Bibliographically approved
Sinelnikova, A., Mandl, T., Agelii, H., Grånäs, O., Marklund, E., Caleman, C. & De Santis, E. (2021). Protein orientation in time-dependent electric fields: orientation before destruction. Biophysical Journal, 120(17), 3709-3717, Article ID S0006-3495(21)00603-2.
Open this publication in new window or tab >>Protein orientation in time-dependent electric fields: orientation before destruction
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2021 (English)In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 120, no 17, p. 3709-3717, article id S0006-3495(21)00603-2Article in journal (Refereed) Published
Abstract [en]

Proteins often have nonzero electric dipole moments, making them interact with external electric fields and offering a means for controlling their orientation. One application that is known to benefit from orientation control is single-particle imaging with x-ray free-electron lasers, in which diffraction is recorded from proteins in the gas phase to determine their structures. To this point, theoretical investigations into this phenomenon have assumed that the field experienced by the proteins is constant or a perfect step function, whereas any real-world pulse will be smooth. Here, we explore the possibility of orienting gas-phase proteins using time-dependent electric fields. We performed ab initio simulations to estimate the field strength required to break protein bonds, with 45 V/nm as a breaking point value. We then simulated ubiquitin in time-dependent electric fields using classical molecular dynamics. The minimal field strength required for orientation within 10 ns was on the order of 0.5 V/nm. Although high fields can be destructive for the structure, the structures in our simulations were preserved until orientation was achieved regardless of field strength, a principle we denote "orientation before destruction."

Place, publisher, year, edition, pages
Cell Press, 2021
National Category
Biophysics
Research subject
Chemistry with specialization in Biophysics
Identifiers
urn:nbn:se:uu:diva-449970 (URN)10.1016/j.bpj.2021.07.017 (DOI)000697106900018 ()34303701 (PubMedID)
Funder
EU, Horizon 2020, 801406Knut and Alice Wallenberg FoundationSwedish Research Council, 2018-00740Carl Tryggers foundation Swedish National Infrastructure for Computing (SNIC), SNIC 2020/15-67Swedish National Infrastructure for Computing (SNIC), SNIC 2019/8-314Swedish National Infrastructure for Computing (SNIC), 2019/30-47
Available from: 2021-09-09 Created: 2021-09-09 Last updated: 2024-01-15Bibliographically approved
Sinelnikova, A., Mandl, T., Östlin, C., Grånäs, O., Brodmerkel, M. N., Marklund, E. & Caleman, C. (2021). Reproducibility in the unfolding process of protein induced by an external electric field. Chemical Science, 12(6), 2030-2038
Open this publication in new window or tab >>Reproducibility in the unfolding process of protein induced by an external electric field
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2021 (English)In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 12, no 6, p. 2030-2038Article in journal (Refereed) Published
Abstract [en]

The dynamics of proteins are crucial for their function. However, commonly used techniques for studying protein structures are limited in monitoring time-resolved dynamics at high resolution. Combining electric fields with existing techniques to study gas phase proteins, such as Single Particle Imaging using Free-electron Lasers and gas phase Small Angle X-ray Scattering, has the potential to open up a new era in time-resolved studies of gas phase protein dynamics. Using molecular dynamics simulations, we identify well-defined unfolding pathways of a protein, induced by experimentally achievable external electric fields. Our simulations show that strong electric fields in conjunction with short pulsed X-ray sources such as Free-electron Lasers can be a new path for imaging dynamics of gas-phase proteins at high spatial and temporal resolution.

Place, publisher, year, edition, pages
Royal Society of ChemistryRoyal Society of Chemistry (RSC), 2021
National Category
Biophysics Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-429912 (URN)10.1039/D0SC06008A (DOI)000619216100039 ()
Funder
EU, Horizon 2020, 801406Swedish Research Council, 2018-00740
Available from: 2021-01-06 Created: 2021-01-06 Last updated: 2024-01-15Bibliographically approved
Mandl, T., Östlin, C., Dawod, I. E., Brodmerkel, M. N., Marklund, E., Martin, A. V., . . . Caleman, C. (2020). Structural Heterogeneity in Single Particle Imaging Using X-ray Lasers. Journal of Physical Chemistry Letters, 11(15), 6077-6083
Open this publication in new window or tab >>Structural Heterogeneity in Single Particle Imaging Using X-ray Lasers
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2020 (English)In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 11, no 15, p. 6077-6083Article in journal (Refereed) Published
Abstract [en]

One of the challenges facing single particle imaging with ultrafast X-ray pulses is the structural heterogeneity of the sample to be imaged. For the method to succeed with weakly scattering samples, the diffracted images from a large number of individual proteins need to be averaged. The more the individual proteins differ in structure, the lower the achievable resolution in the final reconstructed image. We use molecular dynamics to simulate two globular proteins in vacuum, fully desolvated as well as with two different solvation layers, at various temperatures. We calculate the diffraction patterns based on the simulations and evaluate the noise in the averaged patterns arising from the structural differences and the surrounding water. Our simulations show that the presence of a minimal water coverage with an average 3 Å thickness will stabilize the protein, reducing the noise associated with structural heterogeneity, whereas additional water will generate more background noise.

National Category
Biophysics Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-416668 (URN)10.1021/acs.jpclett.0c01144 (DOI)000562064500038 ()32578996 (PubMedID)
Funder
Swedish National Infrastructure for Computing (SNIC), SNIC 2019/8-30EU, Horizon 2020, 801406Swedish Research Council, 201800740Australian Research Council, DP190103027
Available from: 2020-07-28 Created: 2020-07-28 Last updated: 2024-01-09Bibliographically approved
Sinelnikova, A., Mandl, T., Agelii, H., Grånäs, O., Marklund, E., Caleman, C. & De Santis, E.Orientation before destruction. A multiscale molecular dynamics study.
Open this publication in new window or tab >>Orientation before destruction. A multiscale molecular dynamics study
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(English)Manuscript (preprint) (Other academic)
Abstract [en]

The emergence of ultra-fast X-ray free-electron lasers opens the possibility of imaging single molecules in the gas phase at atomic resolution. The main disadvantage of this imaging technique is the unknown orientation of the sample exposed to the X-ray beam, making the three-dimensional reconstruction not trivial. The induced orientation of molecules prior to X-ray exposure can be highly beneficial, as it significantly reduces the number of collected diffraction patterns whilst improving the quality of the reconstructed structure. We present here the possibility of protein orientation using a time-dependent external electric field. We used ab initio simulations on Trp-cage protein to provide a qualitative estimation of the field strength required to break protein bonds, with 45 V/nm as a breaking point value. Furthermore, we simulated, in a classical molecular dynamics approach, the orientation of ubiquitin protein by exposing it to different time-dependent electric fields. The protein structure was preserved for all samples at the moment orientation was achieved, which we denote `orientation before destruction'. Moreover, we find that the minimal field strength required to induce orientation within ten ns of electric field exposure was of the order of 0.5 V/nm. Our results help explain the process of field orientation of proteins and can support the design of instruments for protein orientation.

National Category
Biophysics
Identifiers
urn:nbn:se:uu:diva-434280 (URN)
Available from: 2021-02-08 Created: 2021-02-08 Last updated: 2021-02-08
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