恢复蛋白Recoverin正则模式分析的理论研究

Theoretical Investigation of Recoverin′s Normal Mode Analysis

采用旋转平移块方法对Ca2+/豆蔻酰基开关进行了正则模式分析(NMA).研究结果表明,恢复蛋白(Recoverin)的T态的N-末端与C-末端易于发生刚体逆向旋转,一旦结合Ca2+,很容易发生构象变化,形成具有双向构象转变特征的I态.I态是一个中间结构,既可以发生构象回转到T态,又可以继续相对旋转到R态,使豆蔻酰基完全暴露,从而行使其信号传导生物功能.从低频振动模式分析可以看出,恢复蛋白具有构象转变这一本质属性.

Recoverin is an important branch of neuronal calcium sensor. It had been shown recently that half of the known protein movements can be modelled by using at most two low-frequency normal modes. Hence, we investigated their normal modes by rotational translational block method in order to give a deep insight into the nature of the Ca^2＋-myristoyl switch conformational transition. The normal mode perturbed models of recoverin T-state revealed that the overall motion of the first lowest mode could be described approximately as a converse-rigid-body-swivel around the inter-domain linker. While in the one Ca^2＋ -bound structure, in addition to the converse-rigid-body-swivel motion, an exposure of the myristoyl group is also detected, which was pro- posed as bidirectional conformational transition across the domain interface and facilitates the allosteric transition in signal-transduction processes. These observations indicate that reeoverin is intrinsically dynamic.