用高斯网络模型研究钙调蛋白的构象转变

Dynamics Property of Calmodulin Revealed with Gaussian Network Model

目的:钙调蛋白(Ca M)是细胞内的一种多功能蛋白质传感器,它可以调节细胞中各个区域的靶蛋白。研究Ca M结构的动力学行为和运动趋势。方法:利用高斯网络模型(GNM)分析Ca M在开放和闭合2种形式下的功能运动。结果:Ca M的慢运动模式显示其构象变化主要表现为2个结构域的运动;2种形式的Ca M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倾势。交叉相关图结果显示,Ca M结合Ca2+后,结构域内的相互作用会增强。结论:GNM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Ca M的构象转变规律,以及Ca M底物识别和调节活动的机制。

Objective： To characterize and understand the dynamic changes between the closed and open confor-mations of calmodulin（Ca M）. Methods： The conformational motions and residue fluctuations of two calcium-loadedbut peptide-free structures of Ca M were completely examined using the Gaussian network model（GNM）. Results：The slowest mode of each two forms of Ca M showed that the open-closed motion of the two domains has a com-mon hinge axis centered on the central helix linker, but the two domains of both structures have markedly differ-ent fluctuation range. Most peak residues of the fast modes were located in the calcium-binding loops. The fea-tures of the cross correlation map for two forms were obviously different. Conclusion： The results can help to bet-ter understand the conformational transition of holo Ca M and its interaction with targets, and the mechanism lyingbehind the recognition and regulating activity of Ca M.