Doster Wolfgang, Settles Marcus
Technische Universität München, Physik Department E 13, Garching, Germany.
Biochim Biophys Acta. 2005 Jun 1;1749(2):173-86. doi: 10.1016/j.bbapap.2005.03.010. Epub 2005 Apr 9.
The statistical properties of fast protein-water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays two dynamical components, related to librational motions and anomalous diffusion along the protein surface. Rotational transitions of side chains, in particular of methyl groups, persist in the dehydrated and in the solvent-vitrified protein structure. The interaction with water induces further continuous protein motions on a small scale. Water acts as a plasticizer of displacements, which couple to functional processes such as open-closed transitions and ligand exchange.
通过动态中子散射实验分析了快速蛋白质-水运动的统计特性。利用同位素交换，可以探测蛋白质或水的氢位移。对时域散射函数进行矩分析可得到与模型无关的信息，如时间分辨均方位移和高斯偏差。从这些矩中，可以重建位移分布。水化水表现出两个动力学成分，与沿蛋白质表面的摆动运动和反常扩散有关。侧链的旋转跃迁，特别是甲基的旋转跃迁，在脱水和溶剂玻璃化的蛋白质结构中持续存在。与水的相互作用在小尺度上诱导了蛋白质的进一步连续运动。水作为位移的增塑剂，与诸如开闭转变和配体交换等功能过程相耦合。
