Nakasako Masayoshi
Department of Physics, Faculty of Science and Engineering, Keio University and PRESTO-JST, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522 Japan.
J Biol Phys. 2002 Jun;28(2):129-37. doi: 10.1023/A:1019982220615.
Cryogenic X-ray crystallography has heen applied to investigate thehydration structures of proteins. The amount of hydration water moleculesidentified at cryogenic temperature is more than twice those at ambienttemperature, and the structural models of proteins with a lot of hydrationwater molecules have provided much information to elucidate the static anddynamical characteristics of hydration structures of proteins. On proteinsurface, hydration water molecules distribute non-randomly and stillretain the tetrahedral hydrogen-bond geometry as well as in bulk solvent.In addition, water molecules form clathrate-like arrangements to cover thehydrophobic residues exposed to solvent. The standard interaction geometryenables the three-dimensional extension of hydrogen-bond networks aroundprotein molecules and, simultaneously, ensures the concerted reorganizationof hydration structures during the dynamical motion of proteins at work.The hydration structure analyses at cryogenic temperatures may contributeto understanding physical principles governing the dynamics of `molecularmachines' in aqueous environment.
低温X射线晶体学已被应用于研究蛋白质的水合结构。在低温下鉴定出的水合水分子数量是常温下的两倍多，含有大量水合水分子的蛋白质结构模型为阐明蛋白质水合结构的静态和动态特征提供了许多信息。在蛋白质表面，水合水分子呈非随机分布，并且仍保留四面体氢键几何结构，在本体溶剂中也是如此。此外，水分子形成笼状排列以覆盖暴露于溶剂中的疏水残基。标准的相互作用几何结构使得蛋白质分子周围的氢键网络能够三维扩展，同时确保在蛋白质动态工作过程中水合结构的协同重组。低温下水合结构的分析可能有助于理解在水环境中控制“分子机器”动力学的物理原理。
