School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China.
Phys Rev Lett. 2018 Jun 15;120(24):248101. doi: 10.1103/PhysRevLett.120.248101.
Dynamics of hydration water is essential for the function of biomacromolecules. Previous studies have demonstrated that water molecules exhibit subdiffusion on the surface of biomacromolecules; yet the microscopic mechanism remains vague. Here, by performing neutron scattering, molecular dynamics simulations, and analytic modeling on hydrated perdeuterated protein powders, we found water molecules jump randomly between trapping sites on protein surfaces, whose waiting times obey a broad distribution, resulting in subdiffusion. Moreover, the subdiffusive exponent gradually increases with observation time towards normal diffusion due to a many-body volume-exclusion effect.
水合作用对于生物大分子的功能至关重要。先前的研究表明，水分子在生物大分子表面表现出亚扩散行为；然而，其微观机制尚不清楚。在这里，我们通过对水合氘代蛋白质粉末进行中子散射、分子动力学模拟和分析建模，发现水分子在蛋白质表面的捕获位置之间随机跳跃，其等待时间服从宽分布，导致亚扩散。此外，由于多体体积排阻效应，亚扩散指数随着观察时间的增加逐渐向正常扩散转变。
