钙调蛋白的功能性运动分析

Study on the Functional Motions of Calmodulin

目的:研究钙调蛋白(CaM)结构的动力学行为和运动趋势。方法:利用高斯网络模型(GNM)和各向异性网络模型(ANM),分析CaM在无钙和含钙2种形式下的功能运动。结果:CaM的慢运动模式显示,CaM的构象变化主要表现为2个结构域的运动;2种形式的CaM具有共同的铰链区,铰链区位于分子的中央接头,但二者具有不同的运动趋势。交叉相关图结果显示,CaM结合钙离子后,结构域内的相互作用会增强。结论:GNM和ANM结果可以解释先前报道的实验数据。结果有助于更好地了解CaM的构象转变规律,并会提高对CaM的底物识别和调节活动机制的理解。

Objective： To investigate the dynamic behavior and the motion tendency of calmodulin（CaM）. Methods： Gaussian network（GNM） model and anisotropic network model（ANM） were used to examine the functional motions of CaM in Ca^2＋-free and Ca^2＋-bound forms. Results： The results showed that the conformational transition mainly appeared as the movement of the two lobes. The slowest mode of CaM showed that the two forms have different motion tendency, but have a common hinge axis centered on the central helix linker. The features of the cross correlation map for two forms showed that the binding of Ca^2＋ causes CaM to change its conformation from close to open and formed more contacts within the residues in the two lobes. Conclusion： The mechanism of domain movements of apo- and holo- CaM is investigated with the aid of a GNM. Some features revealed by GNM results were consistent with and could explain the experimental data. The resuhs can lead to a better understanding of the conformational transition of CaM and will improve our understanding of the mechanism lying behind the recognition and regulating activity of CaM.