Levy R M, Dobson C M, Karplus M
Biophys J. 1982 Jul;39(1):107-13. doi: 10.1016/S0006-3495(82)84496-2.
The crystal structure and a 96-ps molecular dynamics simulation used to analyze structural and motional contributions to spin-lattice (T1) relaxation times of phenylalanine and tyrosine C gamma carbons of the pancreatic trypsin inhibitor. The H beta and H delta protons geminal to C gamma are calculated to account for approximately 80% of the dipolar relaxation for each residue. Experimental T1 values for the phenylalanine residues obtained at 25 MHz are observed to be 15-25% longer than estimates based on the rigid crystal structure. It is shown how an increase in T1 can be related to order parameters for the picosecond motional averaging of the important C,H dipolar interactions, and how these order parameters can be calculated from a protein molecular dynamics trajectory.
利用晶体结构和96皮秒的分子动力学模拟分析了胰腺胰蛋白酶抑制剂中苯丙氨酸和酪氨酸Cγ碳的自旋晶格（T1）弛豫时间的结构和运动贡献。与Cγ相连的Hβ和Hδ质子经计算约占每个残基偶极弛豫的80%。在25兆赫兹下获得的苯丙氨酸残基的实验T1值比基于刚性晶体结构的估计值长15 - 25%。展示了T1的增加如何与重要的C - H偶极相互作用的皮秒运动平均的序参数相关，以及这些序参数如何从蛋白质分子动力学轨迹计算得出。
