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Golub M, Gätcke J, Subramanian S, Kölsch A, Darwish T, Howard JK, Feoktystov A, Matsarskaia O, Martel A, Porcar L, Zouni A, Pieper J. "Invisible" Detergents Enable a Reliable Determination of Solution Structures of Native Photosystems by Small-Angle Neutron Scattering. J Phys Chem B 2022; 126:2824-2833. [PMID: 35384657 DOI: 10.1021/acs.jpcb.2c01591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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.
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Affiliation(s)
- M Golub
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
| | - J Gätcke
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - S Subramanian
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - A Kölsch
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - T Darwish
- National Deuteration Facility, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - J K Howard
- National Deuteration Facility, Australian Nuclear Science and Technology Organization, New Illawarra Road, Lucas Heights, NSW 2234, Australia
| | - A Feoktystov
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstr. 1, 85748 Garching, Germany
| | - O Matsarskaia
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - A Martel
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - L Porcar
- Institut Laue-Langevin, 71 Avenue des Martyrs CS 20156, 38042 Grenoble Cedex 9, France
| | - A Zouni
- Humboldt-Universität zu Berlin, Philippstr. 13, 10115 Berlin, Germany
| | - J Pieper
- Institute of Physics, University of Tartu, Wilhelm Ostwald str. 1, 50411 Tartu, Estonia
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