Browsing by Author "Feoktystov, A"

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    “Invisible” detergents enable a reliable determination of solution structures of native photosystems by small-angle neutron scattering
    (ACS Publications, 2022-04-06) Golub, M; Gätcke, J; Subramanian, S; Kölsch, A; Darwish, TA; Feoktystov, A; Matsarskaia, O; Martel, A; Porcar, L; Zouni, A; Pieper, J
    Photosystems I (PSI) and II (PSII) are pigment–protein complexes capable of performing the light-induced charge separation necessary to convert solar energy into a biochemically storable form, an essential step in photosynthesis. Small-angle neutron scattering (SANS) is unique in providing structural information on PSI and PSII in solution under nearly physiological conditions without the need for crystallization or temperature decrease. We show that the reliability of the solution structure critically depends on proper contrast matching of the detergent belt surrounding the protein. Especially, specifically deuterated (“invisible”) detergents are shown to be properly matched out in SANS experiments by a direct, quantitative comparison with conventional matching strategies. In contrast, protonated detergents necessarily exhibit incomplete matching so that related SANS results systematically overestimate the size of the membrane protein under study. While the solution structures obtained are close to corresponding high-resolution structures, we show that temperature and solution state lead to individual structural differences compared with high-resolution structures. We attribute these differences to the presence of a manifold of conformational substates accessible by protein dynamics under physiological conditions. © 2022 American Chemical Society
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    Magnetic nanochain formation studied by small-angle scattering
    (Australian Nuclear Science and Technology Organisation, 2021-11-24) Barnsley, L; Nandakimaran, N; Köhler, T; Feoktystov, A; Gilbert, EP; Brückel, T; Feygenson, M
    Self-assembly of magnetic nanoparticles is of interest due to the broad range of applications in material science and biomedical engineering. Parameters that affect self-assembly in nanoparticles include particle size, the applied magnetic field profile, concentration and synthesis routines. A range of different sizes of magnetic nanoparticles between 5 and 27 nm were investigated using polarized small-angle neutron scattering (SANS) at the KWS-1 instrument operated by the Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) in Garching, Germany and the Quokka instrument operated by the Australian Centre for Neutron Scattering (ACNS) at ANSTO in Lucas Heights, Australia. Iron …© 2021 The Authors