Li Z, Raychaudhuri S, Wand A J
Department of Biological Sciences, State University of New York at Buffalo 14260, USA.
Protein Sci. 1996 Dec;5(12):2647-50. doi: 10.1002/pro.5560051228.
A simple model is used to illustrate the relationship between the dynamics measured by NMR relaxation methods and the local residual entropy of proteins. The expected local dynamic behavior of well-packed extended amino acid side chains are described by employing a one-dimensional vibrator that encapsulates both the spatial and temporal character of the motion. This model is then related to entropy and to the generalized order parameter of the popular "model-free" treatment often used in the analysis of NMR relaxation data. Simulations indicate that order parameters observed for the methyl symmetry axes in, for example, human ubiquitin correspond to significant local entropies. These observations have obvious significance for the issue of the physical basis of protein structure, dynamics, and stability.
一个简单的模型被用来阐明通过核磁共振弛豫方法测量的动力学与蛋白质局部残余熵之间的关系。通过采用一维振子来描述紧密堆积的延伸氨基酸侧链预期的局部动力学行为，该振子囊括了运动的空间和时间特征。然后将此模型与熵以及常用于分析核磁共振弛豫数据的流行“无模型”处理的广义序参量联系起来。模拟表明，例如在人泛素中观察到的甲基对称轴的序参量对应着显著的局部熵。这些观察结果对于蛋白质结构、动力学和稳定性的物理基础问题具有明显的意义。
