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  • 1. Abdurahman, Samir
    et al.
    Höglund, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Höglund, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Biochemistry.
    Vahlne, Anders
    Mutation in the loop C-terminal to the cyclophilin A binding site of HIV-1 capsid protein disrupts proper virus assembly and infectivity2007In: Retrovirology, ISSN 1742-4690, E-ISSN 1742-4690, Vol. 4, p. 19-Article in journal (Refereed)
    Abstract [en]

    We have studied the effects associated with two single amino acid substitution mutations in HIV-1 capsid (CA), the E98A and E187G. Both amino acids are well conserved among all major HIV-1 subtypes. HIV-1 infectivity is critically dependent on proper CA cone formation and mutations in CA are lethal when they inhibit CA assembly by destabilizing the intra and/or inter molecular CA contacts, which ultimately abrogate viral replication. Glu98, which is located on a surface of a flexible cyclophilin A binding loop is not involved in any intra-molecular contacts with other CA residues. In contrast, Glu187 has extensive intra-molecular contacts with eight other CA residues. Additionally, Glu187 has been shown to form a salt-bridge with Arg18 of another N-terminal CA monomer in a N-C dimer. However, despite proper virus release, glycoprotein incorporation and Gag processing, electron microscopy analysis revealed that, in contrast to the E187G mutant, only the E98A particles had aberrant core morphology that resulted in loss of infectivity.

  • 2. Abdurahman, Samir
    et al.
    Vegvari, Akos
    Levi, Michael
    Höglund, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Högberg, Marita
    Tong, Weimin
    Romero, Ivan
    Balzarini, Jan
    Vahlne, Anders
    Isolation and characterization of a small antiretroviral molecule affecting HIV-1 capsid morphology2009In: Retrovirology, ISSN 1742-4690, E-ISSN 1742-4690, Vol. 6, p. 34-Article in journal (Refereed)
    Abstract [en]

    Background: Formation of an HIV-1 particle with a conical core structure is a prerequisite for the subsequent infectivity of the virus particle. We have previously described that glycineamide (G-NH2) when added to the culture medium of infected cells induces non-infectious HIV-1 particles with aberrant core structures. Results: Here we demonstrate that it is not G-NH2 itself but a metabolite thereof that displays antiviral activity. We show that conversion of G-NH2 to its antiviral metabolite is catalyzed by an enzyme present in bovine and porcine but surprisingly not in human serum. Structure determination by NMR suggested that the active G-NH2 metabolite was alpha-hydroxy-glycineamide (alpha-HGA). Chemically synthesized alpha-HGA inhibited HIV-1 replication to the same degree as G-NH2, unlike a number of other synthesized analogues of G-NH2 which had no effect on HIV-1 replication. Comparisons by capillary electrophoresis and HPLC of the metabolite with the chemically synthesized alpha-HGA further confirmed that the antiviral G-NH2-metabolite indeed was alpha-HGA. Conclusion: alpha-HGA has an unusually simple structure and a novel mechanism of antiviral action. Thus, alpha-HGA could be a lead for new antiviral substances belonging to a new class of anti-HIV drugs, i.e. capsid assembly inhibitors.

  • 3. Abdurahman, Samir
    et al.
    Vegvari, Akos
    Youssefi, Masoud
    Levi, Michael
    Höglund, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Andersson, Elin
    Horal, Peter
    Svennerholm, Bo
    Balzarini, Jan
    Vahlne, Anders
    Activity of the small modified amino acid alpha-hydroxy glycineamide on in vitro and in vivo human immunodeficiency virus type 1 capsid assembly and infectivity2008In: Antimicrobial Agents and Chemotherapy, ISSN 0066-4804, E-ISSN 1098-6596, Vol. 52, no 10, p. 3737-3744Article in journal (Refereed)
    Abstract [en]

    Upon maturation of the human immunodeficiency virus type 1 (HIV-1) virion, proteolytic cleavage of the Gag precursor protein by the viral protease is followed by morphological changes of the capsid protein p24, which will ultimately transform the virus core from an immature spherical to a mature conical structure. Virion infectivity is critically dependent on the optimal semistability of the capsid cone structure. We have reported earlier that glycineamide (G-NH2), when added to the culture medium of infected cells, inhibits HIV-1 replication and that HIV-1 particles with aberrant core structures were formed. Here we show that it is not G-NH2 itself but a metabolite thereof, alpha-hydroxy-glycineamide (alpha-HGA), that is responsible for the antiviral activity. We show that alpha-HGA inhibits the replication of clinical HIV-1 isolates with acquired resistance to reverse transcriptase and protease inhibitors but has no effect on the replication of any of 10 different RNA and DNA viruses. alpha-HGA affected the ability of the HIV-1 capsid protein to assemble into tubular or core structures in vitro and in vivo, probably by binding to the hinge region between the N- and C-terminal domains of the HIV-1 capsid protein as indicated by matrix-assisted laser desorption ionization-mass spectrometry results. As an antiviral compound, alpha-HGA has an unusually simple structure, a pronounced antiviral specificity, and a novel mechanism of antiviral action. As such, it might prove to be a lead compound for a new class of anti-HIV substances.

  • 4. Abdurahman, Samir
    et al.
    Youssefi, Masoud
    Höglund, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Vahlne, Anders
    Characterization of the invariable residue 51 mutations of human immunodeficiency virus type 1 capsid protein on in vitro CA assembly and infectivity2007In: Retrovirology, ISSN 1742-4690, E-ISSN 1742-4690, Vol. 4, p. 69-Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The mature HIV-1 conical core formation proceeds through highly regulated protease cleavage of the Gag precursor, which ultimately leads to substantial rearrangements of the capsid (CAp24) molecule involving both inter- and intra-molecular contacts of the CAp24 molecules. In this aspect, Asp51 which is located in the N-terminal domain of HIV-1 CAp24 plays an important role by forming a salt-bridge with the free imino terminus Pro1 following proteolytic cleavage and liberation of the CAp24 protein from the Pr55Gag precursor. Thus, previous substitution mutation of Asp51 to alanine (D51A) has shown to be lethal and that this invariable residue was found essential for tube formation in vitro, virus replication and virus capsid formation. RESULTS: We extended the above investigation by introducing three different D51 substitution mutations (D51N, D51E, and D51Q) into both prokaryotic and eukaryotic expression systems and studied their effects on in vitro capsid assembly and virus infectivity. Two substitution mutations (D51E and D51N) had no substantial effect on in vitro capsid assembly, yet they impaired viral infectivity and particle production. In contrast, the D51Q mutant was defective both for in vitro capsid assembly and for virus replication in cell culture. CONCLUSION: These results show that substitutions of D51 with glutamate, glutamine, or asparagine, three amino acid residues that are structurally related to aspartate, could partially rescue both in vitro capsid assembly and intra-cellular CAp24 production but not replication of the virus in cultured cells.

  • 5.
    Abrahamsson, Maria
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Lundqvist, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry.
    Wolpher, Henriette
    Johansson, Olof
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Eriksson, Lars
    Bergquist, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Rasmussen, Torben
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Becker, Hans-Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Norrby, Per-Ola
    Åkermark, Björn
    Persson, Petter
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Quantum Chemistry.
    Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands.2008In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 47, no 9, p. 3540-3548Article in journal (Refereed)
    Abstract [en]

    The structural effect on the metal-to-ligand charge transfer (MLCT) excited-state lifetime has been investigated in bis-tridentate Ru(II)-polypyridyl complexes based on the terpyridine-like ligands [6-(2,2'-bipyridyl)](2-pyridyl)methane (1) and 2-[6-(2,2'-bipyridyl)]-2-(2-pyridyl)propane (2). A homoleptic ([Ru(2)(2)](2+)) and a heteroleptic complex ([Ru(ttpy)(2)](2+)) based on the new ligand 2 have been prepared and their photophysical and structural properties studied experimentally and theoretically and compared to the results for the previously reported [Ru(1)(2)](2+). The excited-state lifetime of the homoleptic Ru-II complex with the isopropylene-bridged ligand 2 was found to be 50 times shorter than that of the corresponding homoleptic Ru-II complex of ligand 1, containing a methylene bridge. A comparison of the ground-state geometries of the two homoleptic complexes shows that steric interactions involving the isopropylene bridges make the coordination to the central Ru-II ion less octahedral in [Ru(2)(2)](2+) than in [Ru(1)(2))(2+). Calculations indicate that the structural differences in these complexes influence their ligand field splittings as well as the relative stabilities of the triplet metal-to-ligand charge transfer ((MLCT)-M-3) and metal-centered ((MC)-M-3) excited states. The large difference in measured excited-state lifetimes for the two homoleptic Ru-II complexes is attributed to a strong influence of steric interactions on the ligand field strength, which in turn affects the activation barriers for thermal conversion from (MLCT)-M-3 states to short-lived (MC)-M-3 states.

  • 6.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    De Brabandere, Heidi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Sediment Phosphorus Extractants for Phosphorus-31 Nuclear Magnetic Resonance Analysis: A Quantitative Evaluation2007In: Journal of Environmental Quality, ISSN 0047-2425, E-ISSN 1537-2537, Vol. 36, no 3, p. 892-898Article in journal (Refereed)
    Abstract [en]

    The influence of pre-extractant, extractant, and post-extractant on total extracted amounts of P and organic P compound groups measured with 31P nuclear magnetic resonance (31P-NMR) in lacustrine sediment was examined. The main extractants investigated were sodium hydroxide (NaOH) and sodium hydroxide ethylenediaminetetraacetic acid (NaOH-EDTA) with bicarbonate buffered dithionite (BD) or EDTA as pre-extractants. Post extractions were conducted using either NaOH or NaOH-EDTA, depending on the main extractant. Results showed that the most efficient combination of extractants for total P yield was NaOH with EDTA as pre-extractant, yielding almost 50% more than the second best procedure. The P compound groups varying the most between the different extraction procedures were polyphosphates and pyrophosphates. NaOH with BD as pre-extractant was the most efficient combination for these compound groups.

  • 7.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Biogenic phosphorus in oligotrophic mountain lake sediments: Differences in composition measured with NMR spectroscopy2006In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 40, no 20, p. 3705-3712Article in journal (Refereed)
    Abstract [en]

    Phosphorus (P) composition in alkaline sediment extracts from three Swedish oligotrophic mountain lakes was investigated using P-31-NMR spectroscopy. Surface sediments from one natural lake and two mature reservoirs, one of which has received nutrient additions over the last 3 years, were compared with respect to biogenic P composition. The results show significant differences in the occurrence of labile and biogenic P species in the sediments of the different systems. The P compound groups that varied most between these three systems were pyrophosphate and polyphosphates, compound groups known to play an important role in sediment P recycling. The content of these compound groups was lowest in the reservoirs and may indicate a coupling between anthropogenic disturbances (i.e., impoundment) to a water system and the availability of labile P species in the sediment. A statistical study was also conducted to determine the accuracy and reliability of using P-31-NMR spectroscopy for quantification of sediment P forms.

  • 8.
    Ahlgren, Joakim
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry.
    Reitzel, Kasper
    Danielsson, Rolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Rydin, Emil
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I. Faculty of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Biogenic phosphorus in oligotropic mountain lake sediments: Differences in composition measured with NMR spectroscopy2006In: Water Research, no 40, p. 3705-3712Article in journal (Refereed)
  • 9.
    Ahlgren, Joakim
    et al.
    Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
    Reitzel, Kasper
    Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
    De Brabandere, Heidi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
    Release of Organic P Forms from Lake Sediments2011In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 45, no 2, p. 565-572Article in journal (Refereed)
    Abstract [en]

    The effects of different physical and chemical conditions on the decomposition and release of organic and inorganic P compound groups from the sediment of Lake Erken were investigated in a series of laboratory experiments. Conditions investigated were temperature, oxygen level, and the effects of additions of carbon substrate (glucose) and poison (formalin). The effects on the P compound groups were determined by measurements with 31P NMR before and after the experiments, as well as analysis of P in effluent water throughout the experiment. Phosphate analysis of the effluent water showed that oxygen level was the most influential in terms of release rates, with the sediments under anoxic conditions generally releasing more phosphate than the other treatments. 31P NMR showed that the various treatments did influence the P compound group composition of the sediment. In particular, the addition of glucose led to a decrease in orthophosphate and polyphosphate while the addition of formalin led to a decrease in phosphorus lipids, DNAphosphate and polyphosphate. Oxic conditions resulted in an increase in polyphosphates, and anoxic conditions in a decrease in these. Temperature did not seem to affect the composition significantly.

  • 10.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Analytical Chemistry.
    Reitzel, Kasper
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Degradation of organic phosphorus compounds in anoxic Baltic Sea sediments: A P-31 nuclear magnetic resonance study2006In: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 51, no 5, p. 2341-2348Article in journal (Refereed)
    Abstract [en]

    The composition and abundance of phosphorus extracted by NaOH-ethylenediaminetetraacetic acid from anoxic Northwest Baltic Sea sediment was characterized and quantified using solution P-31 nuclear magnetic resonance. Extracts from sediment depths down to 55 cm, representing 85 yr of deposition, contained 18.5 g m(-2) orthophosphate. Orthophosphate monoesters, teichoic acid P, microbial P lipids, DNA P, and pyrophosphate corresponded to 6.7, 0.3, 1.1, 3.0, and 0.03 g P m(-2), respectively. The degradability of these compound groups was estimated by their decline in concentration with sediment depth. Pyrophosphate had the shortest half-life (3 yr), followed by microbial P lipids with a half-life of 5 yr, DNA P (8 yr), and orthophosphate monoesters (16 yr). No decline in concentration with sediment depth was observed for orthophosphate or teichoic acid P.

  • 11.
    Ahlgren, Joakim
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Tranvik, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Gogoll, Adolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Waldebäck, Monica
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Markides, Karin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry, Analytical Chemistry.
    Rydin, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Sediment Depth Attenuation of Biogenic Phosphorus Compounds Measured by 31P NMR2005In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 39, no 3, p. 867-872Article in journal (Refereed)
    Abstract [en]

    Being a major cause of eutrophication and subsequent loss of water quality, the turnover of phosphorus (P) in lake sediments is in need of deeper understanding. A major part of the flux of P to eutrophic lake sediments is organically bound or of biogenic origin. This P is incorporated in a poorly described mixture of autochthonous and allochthonous sediment and forms the primary storage of P available for recycling to the water column, thus regulating lake trophic status. To identify and quantify biogenic sediment P and assess its lability, we analyzed sediment cores from Lake Erken, Sweden, using traditional P fractionation, and in parallel, NaOH extracts were analyzed using 31P NMR. The surface sediments contain orthophosphates (ortho-P) and pyrophosphates (pyro-P), as well as phosphate mono- and diesters. The first group of compounds to disappear with increased sediment depth is pyrophosphate, followed by a steady decline of the different ester compounds. Estimated half-life times of these compound groups are about 10 yr for pyrophosphate and 2 decades for mono- and diesters. Probably, these compounds will be mineralized to ortho-P and is thus potentially available for recycling to the water column, supporting further growth of phytoplankton. In conclusion, 31P NMR is a useful tool to asses the bioavailability of certain P compound groups, and the combination with traditional fractionation techniques makes quantification possible.

  • 12.
    Ahlström, Håkan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Radiology, Oncology and Radiation Science, Radiology.
    Eriksson, Barbro
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Bergström, Mats
    Bjurling, Pernilla
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Långström, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Öberg, Kjell
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences.
    Pancreatic Neuroendocrine Tumors: Diagnosis with PET1995In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 195, no 2, p. 333-337Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    To evaluate the use of carbon-11-labeled L-dihydroxyphenylalanine (L-DOPA) and hydroxytryptophan (5-HTP) in the diagnosis of pancreatic endocrine tumors with positron emission tomography (PET).

    MATERIALS AND METHODS:

    Twenty-two consecutive patients with clinically and biochemically verified pancreatic endocrine tumors were examined with computed tomography (CT) and PET with L-DOPA alone (n = 16) or both C-11-L-DOPA and C-11-5-HTP (n = 6).

    RESULTS:

    Tumor uptake of L-DOPA was found in 11 patients, eight of whom had metastatic disease. Heterogeneity of tracer uptake was noted among different lesions in the same patient (ie, high uptake in some lesions and low uptake in others). Results in patients examined with both L-DOPA and 5-HTP correlated well, but the uptake levels of 5-HTP were higher in two of three patients with positive findings. In two additional patients, CT enabled detection of tumors not detected at PET.

    CONCLUSION:

    The current PET technique can be a valuable complement to CT in demonstration of functional pancreatic endocrine tumors, in particular, glucagonomas, but is less useful in detection of nonfunctional tumors.

  • 13. Aili, Daniel
    et al.
    Enander, Karin
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Liedberg, Bo
    Assembly of polypeptide-functionalized gold nanoparticles through a heteroassociation- and folding-dependent bridging2008In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, no 8, p. 2473-2478Article in journal (Refereed)
    Abstract [en]

    Gold nanoparticles were functionalized with a synthetic polypeptide, de novo-designed to associate with a charge complementary linker polypeptide in a folding-dependent manner. A heterotrimeric complex that folds into two disulphide-linked four-helix bundles is formed when the linker polypeptide associates with two of the immobilized peptides. The heterotrimer forms in between separate particles and induces a rapid and extensive aggregation with a well-defined interpartide spacing. The aggregated particles are redispersed when the disulphide bridge in the linker polypeptide is reduced.

  • 14. Aili, Daniel
    et al.
    Enander, Karin
    Rydberg, Johan
    Lundström, Ingemar
    Baltzer, Lars
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Liedberg, Bo
    Aggregation-Induced Folding of a de novo Designed Polypeptide Immobilized on Gold Nanoparticles2006In: J. Am. Chem. Soc., no 128, p. 2194-2195Article in journal (Refereed)
  • 15. Aili, Daniel
    et al.
    Enander, Karin
    Rydberg, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Nesterenko, Irina
    Björefors, Fredrik
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry II.
    Liedberg, Bo
    Folding Induced Assembly of Polypeptide Decorated Gold Nanoparticles2008In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 130, no 17, p. 5780-5788Article in journal (Refereed)
    Abstract [en]

    Reversible assembly of gold nanoparticles controlled by the homodimerization and folding of an immobilized de novo designed synthetic polypeptide is described. In solution at neutral pH, the polypeptide folds into a helix-loop-helix four-helix bundle in the presence of zinc ions. When immobilized on gold nanoparticles, the addition of zinc ions induces dimerization and folding between peptide monomers located on separate particles, resulting in rapid particle aggregation. The particles can be completely redispersed by removal of the zinc ions from the peptide upon addition of EDTA. Calcium ions, which do not induce folding in solution, have no effect on the stability of the peptide decorated particles. The contribution from folding on particle assembly was further determined utilizing a reference peptide with the same primary sequence but containing both D and L amino acids. Particles functionalized with the reference peptide do not aggregate, as the peptides are unable to fold. The two peptides, linked to the nanoparticle surface via a cysteine residue located in the loop region, form submonolayers on planar gold with comparable properties regarding surface density, orientation, and ability to interact with zinc ions. These results demonstrate that nanoparticle assembly can be induced, controlled, and to some extent tuned, by exploiting specific molecular interactions involved in polypeptide folding.

  • 16. Aili, Daniel
    et al.
    Gryko, Piotr
    Sepulveda, Borja
    Dick, John A. G.
    Kirby, Nigel
    Heenan, Richard
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Liedberg, Bo
    Ryan, Mary P.
    Stevens, Molly M.
    Polypeptide Folding-Mediated Tuning of the Optical and Structural Properties of Gold Nanoparticle Assemblies2011In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 11, no 12, p. 5564-5573Article in journal (Refereed)
    Abstract [en]

    Responsive hybrid nanomaterials with well-defined properties are of significant interest for the development of biosensors with additional applications in tissue engineering and drug delivery. Here, we present a detailed characterization using UV-vis spectroscopy and small angle X-ray scattering of a hybrid material comprised of polypeptide-decorated gold nanoparticles with highly controllable assembly properties. The assembly is triggered by a folding-dependent bridging of the particles mediated by the heteroassociation of immobilized helix-loop-helix polypeptides and a complementary nonlinear polypeptide present in solution. The polypeptides are de novo designed to associate and fold into a heterotrimeric complex comprised of two disulfide-linked four-helix bundles. The particles form structured assemblies with a highly defined interparticle gap (4.8 +/- 0.4 nm) that correlates to the size of the folded polypeptides. Transitions in particle aggregation dynamics, mass-fractal dimensions and ordering, as a function of particle size and the concentration of the bridging polypeptide, are observed; these have significant effects on the optical properties of the assemblies. The assembly and ordering of the particles are highly complex processes that are affected by a large number of variables including the number of polypeptides bridging the particles and the particle mobility within the aggregates. A fundamental understanding of these processes is of paramount interest for the development of novel hybrid nanomaterials with tunable structural and optical properties and for the optimization of nanoparticle-based colorimetric biodetection strategies.

  • 17. Aili, Daniel
    et al.
    Selegard, Robert
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Enander, Karin
    Liedberg, Bo
    Colorimetric Protein Sensing by Controlled Assembly of Gold Nanoparticles Functionalized with Synthetic Receptors2009In: Small, ISSN 1613-6810, Vol. 5, no 21, p. 2445-2452Article in journal (Refereed)
    Abstract [en]

    A novel strategy is described for the colorimetric sensing of proteins, based on polypeptide-functionalized gold nanoparticles. Recognition is accomplished using a polypeptide sensor scaffold designed to specifically bind to the model analyte, human carbonic anhydrase II (HCAII). The extent of particle aggregation, induced by the Zn2+-triggered dimerization and folding of a second polypeptide also present on the surface of the gold nanoparticle, gives a readily detectable colorimetric shift that is dependent on the concentration of the target protein. In the absence of HCAII, particle aggregation results in a major redshift of the plasmon peak, whereas analyte binding prevented the formation of dense aggregates, significantly reducing the magnitude of the redshift. The versatility of the technique is demonstrated using a second model system based on the recognition of a peptide sequence from the tobacco mosaic virus coat protein (TMVP) by a recombinant antibody fragment (Fab57P). Concentrations down to approximate to 10 nM and approximate to 25 nM are detected for HCAII and Fab57P, respectively. This strategy is proposed as a generic platform for robust and specific protein analysis that can be further developed to monitor a wide range of target proteins.

  • 18. Aili, Daniel
    et al.
    Tai, Feng-I
    Enander, Karin
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Liedberg, Bo
    Self-assembly of fibers and nanorings from disulfide-linked helix-loop-helix polypeptides2008In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 47, no 30, p. 5554-5556Article in journal (Refereed)
  • 19.
    Akhtar, Sultan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Rubino, Stefano
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Jansson, Ulf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry.
    Yang, W.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Strömberg, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Strömme, Maria
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Leifer, Klaus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Visualization of functionalization of nano-particles and graphene in the TEM2010In: Advanced Materials Workshop 2010, 2010Conference paper (Refereed)
    Abstract [en]

    Recently, the activity on functionalized nano-objects has strongly increased. Yet, there are, to our knowledge no techniques available that visualize the attachment of molecules to nano-entities such as nanoparticles and graphene. In this work, we show a methodology to analyse the attachment of molecules to nanoparticles and graphene. The difficulty of such transmission electron microscopy (TEM) characterization consists in the high beam sensitivity of these nanoobjects. We employed a high resolution- as well as diffraction contrast-imaging methods to characterize graphene. First, we have developed a method to measure the thickness of free-standing graphene-like layers. The refinement of these imaging techniques enabled the imaging of functionalized C60 (fullerene) on top of a few-layer graphene flake by TEM. We also developed a methodology to visualize the attachment of functionalized gold and magnetic nanoparticles (different sizes) to nonstained and unlabeled single strand DNA-coils. This technique can be used to understand the interaction of a large variety of functionalized nanoparticles with their solution environment and/or macromolecular structures for their large applications.

  • 20. Akoachere, Monique
    et al.
    Iozef, Rimma
    Rahlfs, Stefan
    Deponte, Marcel
    Mannervik, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry. Department of Biochemistry and Organic Chemistry, Biochemistry.
    Creighton, Donald J
    Schirmer, Heiner
    Becker, Katja
    Characterization of the glyoxalases of the malarial parasite Plasmodium falciparum and comparison with their human counterparts.2005In: Biol Chem, ISSN 1431-6730, Vol. 386, no 1, p. 41-52Article in journal (Refereed)
    Abstract [en]

    The glyoxalase system consisting of glyoxalase I (GloI) and glyoxalase II (GloII) constitutes a glutathione-dependent intracellular pathway converting toxic 2-oxoaldehydes, such as methylglyoxal, to the corresponding 2-hydroxyacids. Here we describe a complete glyoxalase system in the malarial parasite Plasmodium falciparum. The biochemical, kinetic and structural properties of cytosolic GloI (cGloI) and two GloIIs (cytosolic GloII named cGloII, and tGloII preceded by a targeting sequence) were directly compared with the respective isofunctional host enzymes. cGloI and cGloII exhibit lower K(m) values and higher catalytic efficiencies (k(cat)/K(m) ) than the human counterparts, pointing to the importance of the system in malarial parasites. A Tyr185Phe mutant of cGloII shows a 2.5-fold increase in K(m) , proving the contribution of Tyr185 to substrate binding. Molecular models suggest very similar active sites/metal binding sites of parasite and host cell enzymes. However, a fourth protein, which has highest similarities to GloI, was found to be unique for malarial parasites; it is likely to act in the apicoplast, and has as yet undefined substrate specificity. Various S-(N-hydroxy-N-arylcarbamoyl)glutathiones tested as P. falciparum Glo inhibitors were active in the lower nanomolar range. The Glo system of Plasmodium will be further evaluated as a target for the development of antimalarial drugs.

  • 21. Albericio, Fernando
    et al.
    Arvidson, Per I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Bisetty, Krishna
    Giral, Ernest
    Govender, Thavendran
    Jali, Samuel
    Kongsaeree, Palangpon
    Kruger, Hendrik G.
    Prabpai, Samran
    Trishomocubane amino acid as a β-turn scaffold2008In: Chemical biology & drug design, ISSN 1747-0277, Vol. 71, no 2, p. 125-130Article in journal (Refereed)
    Abstract [en]

    The synthesis and X-ray structure of two diasteriomeric heptapeptides [Ac-Ala-Ala-Ala-(R/S)-Cage-Ala-Ala-Ala-NH2] with a trishomocubane amino acid as a beta-turn scaffold are reported. The amino acid was synthesized as a racemate and two diastereomeric peptides were obtained. The two peptides were separated by preparative high-pressure liquid chromatography and crystals suitable for X-ray analysis were grown for both diasteriomeric peptides. In general, both the peptides satisfy the criteria for beta-turn conformations. Five of the six Ala residues of both cage peptide crystals satisfy the criteria for 3(10)-helix characteristics and the cage amino acid residue satisfied the m-helix classification. These experimental results confirm previous theoretical studies in our laboratory which predicted that the cage moiety would be a strong/active beta-turn inducer.

  • 22. Albrecht, Christiane
    et al.
    Fechner, Peter
    Honcharenko, Dmytro
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Gauglitz, Günther
    A new assay design for clinical diagnostics based on alternative recognition elements2010In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 25, no 10, p. 2302-2308Article in journal (Refereed)
  • 23. Alonso, Diego
    et al.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Deprotection of Sulfonyl Aziridines1998In: J. Org. Chem., no 63, p. 9455-9461Article in journal (Refereed)
  • 24. Alonso, Diego
    et al.
    Bertilsson, Sophie
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Johnsson, Sandra
    Nordin, Sofia
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Södergren, Mikael
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    New Expedient Route to Both Enantiomers of Nonproteinogenic a-Amino Acid Derivatives from the Unsaturated 2-Aza-Bicyclo Moiety1999In: J. Org. Chem., no 64, p. 2276-2280Article in journal (Refereed)
  • 25. Alonso, Diego
    et al.
    Brandt, Peter
    Nordin, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Andersson, Pher
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Ru(arene)(amino alcohol)-Catalyzed Transfer Hydrogenation of Ketones: Mechanism and Origin of Enantioselectivity1999In: J. Am. Chem. Soc., no 121, p. 9580-9588Article in journal (Refereed)
    Abstract
  • 26. Alonso, Diego
    et al.
    Guijarro, David
    Pinho, Pedro
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Temme, Oliver
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    (1S,3R,4R)-2-Azanorbornylmethanol, an Efficient Ligand for Ruthenium-Catalyzed Asymmetric Transfer Hydrogenation of Ketones1998In: J. Org. Chem., no 63, p. 2749-2751Article in journal (Refereed)
  • 27. Altaib, Mohamed S.
    et al.
    Arvidsson, Per I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Govender, Thavendran
    Maguire, Glenn E. M.
    Makatini, Maya
    Onajole, Oluseye K.
    Kruger, Hendrik G.
    Synthesis and NMR elucidation of novel pentacycloundecane-based peptides2010In: Magnetic Resonance in Chemistry, ISSN 0749-1581, E-ISSN 1097-458X, Vol. 48, no 6, p. 435-442Article in journal (Refereed)
    Abstract [en]

    The synthesis and NMR elucidation of two novel pentacycloundecane (PCU)-based peptides are reported. The PCU cage amino acids were synthesised as racemates and the incorporation of the cage amino acid with (S)-natural amino acids produced diastereomeric peptides. The diastereomeric 'cage' peptides were separated using preparative HPLC and the NMR elucidation of these PCU containing peptides are reported for the first time. The H-1 and C-13 NMR spectra showed series of overlapping signals of the cage skeleton and that of the peptide, making it extremely difficult to resolve the structure using one-dimensional NMR techniques only. The use of two-dimensional NMR techniques proved to be a highly effective tool in overcoming this problem.

  • 28. Amorati, Riccardo
    et al.
    Pedulli, Gian Franco
    Valgimigli, Luca
    Johansson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Engman, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Organochalcogen Substituents in Phenolic Antioxidants2010In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 12, no 10, p. 2326-2329Article in journal (Refereed)
    Abstract [en]

    Little is known about the ED/EW character of organochalcogen substituents and their contribution to the O-H bond dissociation enthalpy (BDE) in phenolic compounds. A series of ortho- and para-(S,Se,Te)R-substituted phenols were prepared and investigated by EPR, IR, and computational methods. Substituents lowered the O-H BDE by >3 kcal/mol in the para position, while the ortho-effect was modest due to hydrogen bonding ( approximately 3 kcal/mol) to the O-H group.

  • 29. Anderot, Maria
    et al.
    Nilsson, Mikael
    Vegvari, Akos
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Moeller, Horn
    van de Weert, Marco
    Isaksson, Roland
    Determination of dissociation constants between polyelectrolytes and proteins by affinity capillary electrophoresis2009In: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 877, no 10, p. 892-896Article in journal (Refereed)
    Abstract [en]

    In this manuscript we report the binding affinity between two model proteins, human serum albumin (HSA) and ribonuclease A (RNase A), and negatively charged polyelectrolytes, two different heparin fractions and dextran sulfate, by means of partial filling and affinity capillary electrophoresis. The apparent dissociation constants, K-d, obtained by use of the partial-filling method, between HSA and heparin (17 kDa), heparin (3 kDa) and dextran sulfate (8 kDa) were 33 and 307 mu M, respectively. A new method was developed to determine affinities that take in account different migration directions between the protein and the polyelectrolyte, which was required to study RNase A. By use of this affinity capillary electrophoresis two K-d values were observed for the interaction between RNase A and heparin 17 kDa, yielding a high affinity binding with K-d1 0.0075 mu M, and a lower affinity binding with K-d2 8.7 mu M. For dextran sulfate 8 kDa these K-d values were 0.027 and 10.4 mu M, respectively. Heparin 3 kDa only showed a single K-d value of 0.52 mu M. The results show that the magnitude of the binding affinity depends on the type of polyelectrolyte and its molecular weight. (C) 2009 Elsevier B.V. All rights reserved.

  • 30.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Physical Organic Chemistry.
      Appendix: Experimental details for tricarbonyl chromium complexes2011Other (Other academic)
  • 31.
    Andersson, Claes-Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Physical Organic Chemistry.
    Chemistry of Carbon Nanostructures: Functionalization of Carbon Nanotubes and Synthesis of Organometallic Fullerene Derivatives2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is based on two main parts. The first part concerns purification and functionalization of carbon nanotubes (papers I-III), and the second part is related to the synthesis of organometallic fullerene derivatives (papers IV-VII):

    Two oxidative methods involving aqueous nitric acid were compared with respect to their capability to introduce carboxylic groups into single walled carbon nanotubes, and several literature methods for esterification and amidation of these groups have been evaluated with focus on efficiency and reproducibility in forming covalently functionalized products soluble in organic media. Amidation proceeding via a SWNT-(COCl)n intermediate yielded the expected covalent product, whereas carboxylate salt formation dominated with other attempted methods. Esterification was achieved via the acyl chloride method and via alkylation of SWNT-(COO)n, the latter being the more efficient method.

    A new, reagent-free method for purification of single- and multi walled carbon nanotubes has been developed. Microwave treatment dissociates non-nanotube carbon and disperses it into an organic solvent, resulting in very pure carbon nanotubes within a few minutes of heating, without the involvement of acidic/oxidative reagents. According to thermogravimetric analysis, Raman and IR spectroscopy, as well as SEM, the process yields nanotubes with a low degree of defects.

    A non-covalent approach has been employed to prepare nanotubes functionalized with glycosides. Derivatives of galactose and lactose were covalently linked to a pyrene moiety and the thus formed pyrene-glycosides were non-covalently attached to single- and multi walled carbon nanotubes by π-π interactions. Fluorescence titrations have been used to quantify the formed supramolecular assemblies, which for SWNTs exhibits increased water solubility.

    A fulleropyrrolidine-(tricarbonyl)chromium complex was synthesized and fully characterized. IR spectroelectrochemistry was used to probe the redox state of the fullerene and provided evidence for electronic communication between the two electroacive moieties. A C60-ferrocene-C60 triad system was synthesized and characterized. Cyclic voltammetry and fluorescence studies suggested electronic communication between ferrocene and the two fullerenes. Finally, the synthesis and initial characterization of short fullerene-ferrocene oligomers are presented.

    List of papers
    1. Reproducibility and efficiency of carbon nanotube end-group generation and functionalization
    Open this publication in new window or tab >>Reproducibility and efficiency of carbon nanotube end-group generation and functionalization
    2009 (English)In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 26, p. 4421-4428Article in journal (Refereed) Published
    Abstract [en]

    In a systematic fashion, several methods for esterification and  amidation of single-walled carbon nanotubes have been evaluated with   focus on efficiency and reproducibility in forming covalently   functionalized products soluble in organic media. The outcome of   transformations was determined using IR, Raman and NMR spectroscopy and   by thermogravimetric analysis (TGA). Amidation proceeding via a   SWNT-(COCl)(n) intermediate yielded the expected covalent product,  whereas carboxylate salt formation dominated with other attempted   methods. Esterification was achieved via the acyl chloride method and   via alkylation of SWNT-(COO-)(n), the latter being the more efficient   method. A non-covalent solubilizing interaction was obtained for RNH2   but not for ROH (R = octadecyl), proving that the most important   non-covalent interaction between oxidatively cleaned SWNTs and   octadecylamine is a salt formation. The outcome of the secondary   functionalization of carboxyl units is highly reproducible for   experiments carried out on the same batch of SWNT-(COOH)(n). Normalization of the outcome of the secondary functionalization to the   composition of the different batches of starting materials reveals an overall high reproducibility of the secondary function alizations. The   differences in outcome related to different commercial SWNT batches   from the same synthetic procedure is negligible compared to that   resulting from differences in overall carboxyl content after the   primary HNO3 oxidative cleaning step. Hence, the composition of   purified SWNT starting materials always needs to be assessed, in particular before drawing any conclusions concerning differences in   outcome from reaction systems involving different sources of SWNT  material.

    Keywords
    Nanotubes, Nanotechnology, Functionalization, Esterification, Amidation
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-112369 (URN)10.1002/ejoc.200900534 (DOI)000270014700006 ()
    Available from: 2010-01-13 Created: 2010-01-13 Last updated: 2017-12-12Bibliographically approved
    2. The reagent-free, microwave-assisted purification of carbon nanotubes
    Open this publication in new window or tab >>The reagent-free, microwave-assisted purification of carbon nanotubes
    Show others...
    2010 (English)In: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 34, no 10, p. 2275-2280Article in journal (Refereed) Published
    Abstract [en]

    We have developed a microwave-assisted, reagent-free method for the efficient primary purification of MW and SW carbon nanotubes that is extremely fast compared to previously reported processes. The treatment dissociates and disperses non-nanotube carbon in an organic solvent to yield very pure carbon nanotubes within a few minutes of heating and a simple filtration, without the involvement of acidic/oxidative reagents. According to thermogravimetric analysis, Raman and IR spectroscopy, as well as scanning and transmission electron microscopy, the process yields pure nanotubes with a low degree of defects.

    National Category
    Chemical Sciences Inorganic Chemistry Engineering and Technology
    Research subject
    Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-134674 (URN)10.1039/c0nj00087f (DOI)000282219600029 ()
    Available from: 2010-12-01 Created: 2010-11-30 Last updated: 2018-06-04Bibliographically approved
    3. Reversible Non-Covalent Derivatisation of Carbon Nanotubes with Glycosides
    Open this publication in new window or tab >>Reversible Non-Covalent Derivatisation of Carbon Nanotubes with Glycosides
    2009 (English)In: Soft Matter, ISSN 1744-683X, Vol. 5, no 14, p. 2713-2716Article in journal (Refereed) Published
    Abstract [en]

    SWNTs and MWNTs have been non-covalently functionalized with glycosides   in a reversible manner, and fluorescence titrations have been used to   quantify the formed supramolecular assemblies which for SWNTs exhibits   increased water solubility.

    Keywords
    carbon nanotube
    National Category
    Chemical Sciences
    Identifiers
    urn:nbn:se:uu:diva-112366 (URN)10.1039/ B907791J (DOI)000268783500006 ()
    Available from: 2010-01-13 Created: 2010-01-13 Last updated: 2011-11-04Bibliographically approved
    4. Synthesis and IR Spectroelectrochemical Studies of a [60]Fulleropyrrolidine-(tricarbonyl)chromium Complex: Probing C-60 Redox States by IR Spectroscopy
    Open this publication in new window or tab >>Synthesis and IR Spectroelectrochemical Studies of a [60]Fulleropyrrolidine-(tricarbonyl)chromium Complex: Probing C-60 Redox States by IR Spectroscopy
    2011 (English)In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11, p. 1744-1749Article in journal (Refereed) Published
    Abstract [en]

    The synthesis of a new fulleropyrrolidine-(tricarbonyl)chromium complex: 1-methyl-2-(4-methoxyphenyl)-3,4-[60]fulleropyrrolidine-(tricarbonyl)chromium is described together with its characterization by IR, NMR and cyclic voltammetry. IR spectro-electrochemistry has been used to probe the redox level of the fullerene derivative via the relative position of the vibrational bands of the CO ligands, which are sensitive to the electronic state of the complex. Other strategies to incorporate a tricarbonylchromium moiety to fullerene C60 are also briefly discussed and evaluated.

    Place, publisher, year, edition, pages
    John Wiley & Sons, 2011
    Keywords
    Fullerenes, Chromium, IR spectroscopy, Cyclic voltammetry, Redox chemistry, Electrochemistry
    National Category
    Chemical Sciences
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-148456 (URN)10.1002/ejic.201100011 (DOI)000289354900008 ()
    Available from: 2011-03-07 Created: 2011-03-07 Last updated: 2017-12-11
    5. Synthesis and characterization of a ferrocene-linked bis-fullerene[60] dumbbell
    Open this publication in new window or tab >>Synthesis and characterization of a ferrocene-linked bis-fullerene[60] dumbbell
    2012 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 41, no 8, p. 2374-2381Article in journal (Refereed) Published
    Abstract [en]

    A new [60]fullerene dumbbell consisting of two fulleropyrrolidines connected to a central ferrocene unit by amide linkages has been prepared and fully characterized by elemental analysis, 1H NMR, UV/Vis, fluorescence and mass spectrometry. The electrochemical properties as determined by cyclic voltammetry show ground state electronic communication between the ferrocene and the fullerene units. In addition, the preparaton of a ferrocene building block for an alternative linking approach is presented.

    Keywords
    Fullerenes, Ferrocene, Dumbbell, Cyclic voltammetry
    National Category
    Organic Chemistry Inorganic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry; Chemistry with specialization in Inorganic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-158905 (URN)10.1039/C2DT12097F (DOI)000300186100022 ()
    Available from: 2011-09-19 Created: 2011-09-19 Last updated: 2017-12-08Bibliographically approved
    6. Short ferrocene-[60]fulleropyrrolidine oligomers. A preliminary account on synthetic studies
    Open this publication in new window or tab >>Short ferrocene-[60]fulleropyrrolidine oligomers. A preliminary account on synthetic studies
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A synthetic strategy towards short fullerene based organometallic oligomers is reported. The synthetic approach is based on the secondary functionalization of N-unsubstituted fulleropyrrolidines with ferrocene dicarboxylic acid chloride. Preliminary characterization by mass spectrometry, UV/Vis and NMR suggest a trimer or tetramer structure.

    Keywords
    Fullerenes / Oligomers / Ferrocene
    National Category
    Organic Chemistry
    Research subject
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-159308 (URN)
    Note
    preliminärt manuskriptAvailable from: 2011-09-27 Created: 2011-09-27 Last updated: 2011-11-04
    7.   Appendix: Experimental details for tricarbonyl chromium complexes
    Open this publication in new window or tab >>  Appendix: Experimental details for tricarbonyl chromium complexes
    2011 (English)Other (Other academic)
    Place, publisher, year, pages
    Uppsala: Acta Universitatis Upsaliensis, 2011
    National Category
    Organic Chemistry
    Research subject
    Chemistry with specialization in Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-159309 (URN)
    Available from: 2011-09-27 Created: 2011-09-27 Last updated: 2011-11-04
  • 32.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Synthesis and IR Spectroelectrochemical Studies of a [60]Fulleropyrrolidine-(tricarbonyl)chromium Complex: Probing C-60 Redox States by IR Spectroscopy2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11, p. 1744-1749Article in journal (Refereed)
    Abstract [en]

    The synthesis of a new fulleropyrrolidine-(tricarbonyl)chromium complex: 1-methyl-2-(4-methoxyphenyl)-3,4-[60]fulleropyrrolidine-(tricarbonyl)chromium is described together with its characterization by IR, NMR and cyclic voltammetry. IR spectro-electrochemistry has been used to probe the redox level of the fullerene derivative via the relative position of the vibrational bands of the CO ligands, which are sensitive to the electronic state of the complex. Other strategies to incorporate a tricarbonylchromium moiety to fullerene C60 are also briefly discussed and evaluated.

  • 33.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Reproducibility and efficiency of carbon nanotube end-group generation and functionalization2009In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 26, p. 4421-4428Article in journal (Refereed)
    Abstract [en]

    In a systematic fashion, several methods for esterification and  amidation of single-walled carbon nanotubes have been evaluated with   focus on efficiency and reproducibility in forming covalently   functionalized products soluble in organic media. The outcome of   transformations was determined using IR, Raman and NMR spectroscopy and   by thermogravimetric analysis (TGA). Amidation proceeding via a   SWNT-(COCl)(n) intermediate yielded the expected covalent product,  whereas carboxylate salt formation dominated with other attempted   methods. Esterification was achieved via the acyl chloride method and   via alkylation of SWNT-(COO-)(n), the latter being the more efficient   method. A non-covalent solubilizing interaction was obtained for RNH2   but not for ROH (R = octadecyl), proving that the most important   non-covalent interaction between oxidatively cleaned SWNTs and   octadecylamine is a salt formation. The outcome of the secondary   functionalization of carboxyl units is highly reproducible for   experiments carried out on the same batch of SWNT-(COOH)(n). Normalization of the outcome of the secondary functionalization to the   composition of the different batches of starting materials reveals an overall high reproducibility of the secondary function alizations. The   differences in outcome related to different commercial SWNT batches   from the same synthetic procedure is negligible compared to that   resulting from differences in overall carboxyl content after the   primary HNO3 oxidative cleaning step. Hence, the composition of   purified SWNT starting materials always needs to be assessed, in particular before drawing any conclusions concerning differences in   outcome from reaction systems involving different sources of SWNT  material.

  • 34.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Physical Organic Chemistry.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Physical Organic Chemistry.
    Short ferrocene-[60]fulleropyrrolidine oligomers. A preliminary account on synthetic studiesManuscript (preprint) (Other academic)
    Abstract [en]

    A synthetic strategy towards short fullerene based organometallic oligomers is reported. The synthetic approach is based on the secondary functionalization of N-unsubstituted fulleropyrrolidines with ferrocene dicarboxylic acid chloride. Preliminary characterization by mass spectrometry, UV/Vis and NMR suggest a trimer or tetramer structure.

  • 35.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Lahman, Martina
    Oscarson, Stefan
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Reversible Non-Covalent Derivatisation of Carbon Nanotubes with Glycosides2009In: Soft Matter, ISSN 1744-683X, Vol. 5, no 14, p. 2713-2716Article in journal (Refereed)
    Abstract [en]

    SWNTs and MWNTs have been non-covalently functionalized with glycosides   in a reversible manner, and fluorescence titrations have been used to   quantify the formed supramolecular assemblies which for SWNTs exhibits   increased water solubility.

  • 36.
    Andersson, Malena
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry. Department of Biochemistry and Organic Chemistry, Biochemistry.
    Mannervik, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry. Department of Biochemistry and Organic Chemistry, Biochemistry.
    Exploring protein evolution by saturation mutagenesis of the GST M2-2 active site residue 2102005In: FEBS Journal, Vol. 272, p. 81 Suppl-Article in journal (Other scientific)
  • 37. Andersson, Per Ola
    et al.
    Lundquist, Margaretha
    Tegler, Lotta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Börjegren, Susanne
    Baltzer, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Österlund, Lars
    A Novel ATR-FTIR Approach for Characterisation and Identification of Ex Situ Immobilised Species2007In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 8, no 5, p. 712-722Article in journal (Refereed)
    Abstract [en]

    We demonstrate a novel method to analyse ex situ prepared protein chips by attenuated total reflection Fourier IR spectroscopy (ATR-FTIR), which circumvents tedious functionalisation steps of internal reflection elements (IREs), and simultaneously allows for complementary measurements by other analytical techniques. This concept is proven by utilising immobilised metal affinity capture (IMACTM) chips containing about 10 m thick films of copolymers coated with nitrilotriacetic acid (NTA) groups, which originally was manufactured for surface enhanced laser desorption ionisation (SELDI) spectrometry. Three immobilisation steps were analysed by ATR-FTIR spectroscopy: 1) NTA complexation with nickel(II) ions 2) binding of two histidine (His)-tagged synthetic peptides of 25 (25-His6) and 48 (48-His6) amino acids to the NTA-groups and 3) attachment of a ligand, mesyl amide, to the surface-bound 48-His6. Despite interference from H2O, both amide I and II were well resolved. Utilising peptide adsorption in the thick copolymer matrix yields a high saturation peptide concentration of 100 mg mL-1 and a dissociation constant of 116±11 M, as determined by a detailed analysis of the Langmuir adsorption isotherm. The mesyl amide ligand was directly seen in the raw ATR-FTIR spectrum with specific peaks in the fingerprint region at 1172 and 1350 cm-1. Several aspects of the fine structure of the amide I band of the peptide were analysed: influences from secondary structure, amino side chains and competing contamination product. We believe that this approach has great potential as a stand-alone or complementary analytical tool for determination of the chemical composition of functionalised surfaces. We emphasise further that with this approach no chemical treatment of IREs is needed; the chips can be regenerated and reused, and applied in other experimental set-ups.

  • 38.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Development of a new methodology for the preparation of optically active alcohols*2004In: Pure Appl. Chem., Vol. 76, no 3, p. 547-555Article in journal (Refereed)
  • 39.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    On the Stereochemical Outcome of the McMurry Coupling of Acetophenone. A Reinvestigation1994In: Tetrahedron Letters, Vol. 35, no 16, p. 2609-2610Article in journal (Refereed)
  • 40.
    Andersson, Pher
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Regio- and Stereoselective Deuteration of Allylic Chlorides Controlled by Neighboring Alcohol or Ether Groups1996In: J. Org. Chem., no 61, p. 4154-4156Article in journal (Refereed)
  • 41.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Aranyos, Attila
    Palladium-Mediated Stereo- and Regioselective Tandem-Cyclization-Carbonylations of 1,3-dienes1994In: Tetrahedron Letters, Vol. 35, no 25, p. 4441-4444Article in journal (Refereed)
  • 42.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E.
    Palladium-Catalyzed Tandem Cyclization of 4,6- and 5,7-Diene Amides. A New Route towards the Pyrrolizidine and Indolizidine Alkaloids1992In: J. Am. Chem. Soc., Vol. 114, no 22, p. 8696-8698Article in journal (Refereed)
  • 43.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E.
    Synthesis of Furanoid Terpenes via an Efficient Palladium-Catalyzed Cyclization of 4,6-Dienols1991In: J. Org. Chem., Vol. 56, no 18, p. 5349-5353Article in journal (Refereed)
  • 44.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Bäckvall, Jan-E.
    Synthesis of Heterocyclic Natural Products via Regio- and Stereocontrolled Palladium-Catalyzed Reactions1996In: Advances in Heterocyclic Natural Product Synthesis, JAI Press Inc, Greenwich , 1996, p. 179-215Chapter in book (Refereed)
  • 45.
    Andersson, Pher G.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Regio- and Stereoselective Deuteration of Allylic Chlorides Controlled by Neighboring Alcohol or Ether Groups1996In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 61, no 12, p. 4154-4156Article in journal (Refereed)
  • 46.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Guijarro, David
    Tanner, David
    Preparation and Use of Aziridino Alcohols as Promoters for the Enantioselective Addition of Dialkylzinc Reagents to N-(Diphenylphosphinoyl) Imines1997In: J. Org. Chem., no 62, p. 7364-7375Article in journal (Refereed)
  • 47.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Guijarro, David
    Tanner, David
    Simple Aziridino Alcohols as Chiral Ligands. Enantioselective Additions of Diethylzinc to N-Diphenylphosphinoylimines1996In: Synlett, no 8, p. 727-728Article in journal (Refereed)
  • 48.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Harden, Adrian
    Tanner, David
    Norrby, Per-Ola
    Studies of Allylic Substitution Catalysed by a Palladium Complex of a C2-Symmetric Bis(aziridine): Preparation and NMR Spectroscopic Investigation of a Chiral n-Allyl Species1995In: Chem. Eur. J., no 1, p. 12-16Article in journal (Refereed)
  • 49.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Johansson, Fredrik
    Tanner, David
    Enantioselective Addition of Organolithium Reagents to Imines Mediated by C2-Symmetric Bis(aziridine) Ligands1998In: Tetrahedron, no 54, p. 11549-11566Article in journal (Refereed)
  • 50.
    Andersson, Pher
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Chemistry. Department of Biochemistry and Organic Chemistry, Organic Chemistry I.
    Nilsson, Ylva
    Bäckvall, Jan-E.
    Palladium-Catalyzed Oxaspirocyclizations1994In: Tetrahedron, Vol. 50, no 2, p. 559-572Article in journal (Refereed)
1234567 1 - 50 of 863
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