University of Alaska--Anchorage, Anchorage, Alaska 99508, USA.
J Am Chem Soc. 2010 Mar 31;132(12):4038-9. doi: 10.1021/ja909599k.
Methyl groups are thought to dominate the dynamics of proteins after slow collective modes of motion freeze out in a glass-transition process. In this work we investigate methyl group dynamics of a key hydrophobic core leucine residue in chicken villin headpiece subdomain protein at 140-4 K using deuteron NMR longitudinal relaxation measurements. A distinct increase in the apparent activation energy is observed at approximately 95 K, indicating an abrupt freezing of methyl group dynamics. Relaxation times at temperatures below 60 K are dominated by the deuteron tunneling mechanism.
甲基基团被认为在玻璃化转变过程中，当缓慢的集体运动模式冻结后，主导着蛋白质的动力学。在这项工作中，我们使用氘核 NMR 纵向弛豫测量研究了鸡绒毛蛋白头部亚域蛋白中关键疏水性核心亮氨酸残基的甲基基团动力学，在 140-4 K 下。在大约 95 K 时，观察到表观活化能的明显增加，表明甲基基团动力学的突然冻结。温度低于 60 K 时的弛豫时间主要由氘核隧道机制决定。
