Mirror-image antiparallel β-sheets organize water molecules into superstructures of opposite chirality
Mirror-image antiparallel β-sheets organize water molecules into superstructures of opposite chirality
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DOI：
10.1073/pnas.2015567117
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发表时间：
2020-12-29
影响因子：
11.1
通讯作者：
Yan, Elsa C. Y.
中科院分区：
文献类型：
--
作者：
Perets, Ethan A.;Konstantinovsky, Daniel;Yan, Elsa C. Y.
生物分子水合作用是生物功能的基础。利用相分辨手性和频率产生光谱（SFG），研究了自组装反平行β -片蛋白周围水分子的分子结构和相互作用。我们发现水的O-H拉伸振动模式的手性响应的相位与（L-）或（D-）反平行β -片的绝对手性翻转。因此，我们可以得出结论，（D-）反平行β -片将水溶剂组织成与（L-）反平行β -片相反手性的手性超分子结构。我们用分子动力学在原子分辨率上表征手性水的超结构。结果表明，反平行β -片的宏观手性破坏了周围水分子组合的对称性。我们还计算了（L-）和（D-） LK7 β周围水的手性SFG响应，以确认手性水结构的存在。我们的结果提供了一个不同的视角，并介绍了实验和计算方法来阐明生物大分子的水合作用。这些发现暗示了水溶剂在生物分子相互作用的手性选择性和生物世界中同手性的分子起源中的潜在重要作用，但在很大程度上尚未被探索。
Biomolecular hydration is fundamental to biological functions. Using phase-resolved chiral sum-frequency generation spectroscopy (SFG), we probe molecular architectures and interactions of water molecules around a self-assembling antiparallel beta-sheet protein. We find that the phase of the chiroptical response from the O-H stretching vibrational modes of water flips with the absolute chirality of the (L-) or (D-) antiparallel beta-sheet. Therefore, we can conclude that the (D-) antiparallel beta-sheet organizes water solvent into a chiral supermolecular structure with opposite handedness relative to that of the (L-) antiparallel beta-sheet. We use molecular dynamics to characterize the chiral water superstructure at atomic resolution. The results show that the macroscopic chirality of antiparallel beta-sheets breaks the symmetry of assemblies of surrounding water molecules. We also calculate the chiral SFG response of water surrounding (L-) and (D-) LK7 beta to confirm the presence of chiral water structures. Our results offer a different perspective as well as introduce experimental and computational methodologies for elucidating hydration of biomacromolecules. The findings imply potentially important but largely unexplored roles of water solvent in chiral selectivity of biomolecular interactions and the molecular origins of homochirality in the biological world.