Jülich Centre for Neutron Science (JCNS-1) and Institute for Complex Systems (ICS-1), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
Phys Chem Chem Phys. 2019 Aug 28;21(34):18727-18740. doi: 10.1039/c9cp01768b.
The plant stress protein COR15A stabilizes chloroplast membranes during freezing. COR15A is an intrinsically disordered protein (IDP) in aqueous solution, but acquires an α-helical structure during dehydration or the increase of solution osmolarity. We have used small- and wide-angle X-ray scattering (SAXS/WAXS) combined with static and dynamic light scattering (SLS/DLS) to investigate the structural and hydrodynamic properties of COR15A in response to increasing solution osmolarity. Coarse-grained ensemble modelling allowed a structure-based interpretation of the SAXS data. Our results demonstrate that COR15A behaves as a biomacromolecule with polymer-like properties which strongly depend on solution osmolarity. Biomacromolecular self-assembly occurring at high solvent osmolarity is initiated by the occurrence of two specific structural subpopulations of the COR15A monomer. The osmolarity dependent structural selection mechanism is an elegant way for conformational regulation and assembly of COR15A. It highlights the importance of the polymer-like properties of IDPs for their associated biological function.
植物应激蛋白 COR15A 在冷冻过程中稳定叶绿体膜。COR15A 在水溶液中是一种无规卷曲的蛋白质（IDP），但在脱水或溶液渗透压增加时会获得α-螺旋结构。我们使用小角和广角 X 射线散射（SAXS/WAXS）结合静态和动态光散射（SLS/DLS）来研究 COR15A 对溶液渗透压增加的结构和流体力学性质的响应。粗粒度的整体模型允许对 SAXS 数据进行基于结构的解释。我们的结果表明，COR15A 表现为具有聚合物特性的生物大分子，这些特性强烈依赖于溶液渗透压。在高溶剂渗透压下发生的生物大分子自组装是由 COR15A 单体的两个特定结构亚群的出现引发的。渗透压依赖性结构选择机制是 COR15A 构象调节和组装的一种优雅方式。它强调了 IDP 的聚合物样性质对其相关生物学功能的重要性。
