Goddard Yanina A, Korb Jean-Pierre, Bryant Robert G
Chemistry Department, University of Virginia, Charlottesville, Virginia, USA.
Biophys J. 2006 Nov 15;91(10):3841-7. doi: 10.1529/biophysj.106.090126. Epub 2006 Aug 25.
The nuclear magnetic transverse decay and the proton second moment of bovine serum albumin samples dry and hydrated with different water isotope compositions show that at temperatures around 170 K, there is a dramatic change in the dynamics of the water associated with the protein interface. By comparison, observation of the protein protons when hydrated with deuterium oxide provides no evidence for significant dynamical changes near 170 K. The proton second moment of the hydrated protein shows that the protein structure becomes more open with increasing hydration from the lyophilized condition and that the side chains extend from the protein surface into the solvent in the hydrated but not the dry cases. The proton second moment of serum albumin hydrated with H(2)O increases dramatically with decreasing temperature near 170 K, demonstrating that the water forms a rigid solid around the protein which effectively fills the surface irregularities created by the protein fold. Solvation with dimethyl sulfoxide yields small effects compared with water.
用不同水同位素组成进行干燥和水合处理的牛血清白蛋白样品的核磁共振横向弛豫和质子二阶矩表明，在170K左右的温度下，与蛋白质界面相关的水的动力学发生了显著变化。相比之下，用重水进行水合处理时对蛋白质质子的观察没有提供在170K附近有显著动力学变化的证据。水合蛋白质的质子二阶矩表明，随着从冻干状态开始水合程度的增加，蛋白质结构变得更加开放，并且在水合而非干燥的情况下，侧链从蛋白质表面延伸到溶剂中。用H₂O水合的血清白蛋白的质子二阶矩在接近170K时随着温度降低而急剧增加，这表明水在蛋白质周围形成了刚性固体，有效地填充了由蛋白质折叠产生的表面不规则性。与水相比，用二甲基亚砜进行溶剂化产生的影响较小。
