"Invisible" Detergents Enable a Reliable Determination of Solution Structures of Native Photosystems by Small-Angle Neutron Scattering
"Invisible" Detergents Enable a Reliable Determination of Solution Structures of Native Photosystems by Small-Angle Neutron Scattering
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DOI：
10.1021/acs.jpcb.2c01591
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发表时间：
2022-04-21
影响因子：
3.3
通讯作者：
Pieper, J.
中科院分区：
文献类型：
--
作者：
Golub, M.;Gaetcke, J.;Pieper, J.
光系统 I (PSI) 和 II (PSII) 是色素-蛋白质复合物，能够进行光诱导的电荷分离，将太阳能转化为可生化储存的形式，这是光合作用的重要步骤。小角中子散射 (SANS) 的独特之处在于，可以在接近生理条件下提供溶液中 PSI 和 PSII 的结构信息，而无需结晶或降低温度。我们表明，溶液结构的可靠性关键取决于蛋白质周围洗涤剂带的适当对比度匹配。特别是，通过与传统匹配策略的直接、定量比较，特定氘化（“不可见”）去污剂在 SANS 实验中显示出正确匹配。相反，质子化去污剂必然表现出不完全匹配，因此相关的 SANS 结果系统地高估了所研究的膜蛋白的大小。虽然获得的溶液结构接近相应的高分辨率结构，但我们表明，与高分辨率结构相比，温度和溶液状态导致个体结构差异。我们将这些差异归因于生理条件下蛋白质动力学可访问的多种构象亚状态的存在。
Photosystems I (PSI) and II (PSII) arc 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.