【摘要】 恢复蛋白Recoverin是一重要的神经钙传感蛋白.为澄清EF-hand与Ca2+耦合/去耦合作用机制,采用拉伸分子动力学(SMD)方法对其进行了一系列等外力和等速度的非平衡分子动力学模拟.研究结果表明EF-2和EF-3loop区氨基酸螯合Ca2+能力大小顺序分别为Asn-76<Thr-80<Glu-85<Asp-74<Asp-78和Thr-116<Glu-121<Asp-110<Asn-114<Asp-112.结构域EF-3比EF-2耦合Ca2+离子的能力强.EF-handloop环中的Asp-78和Asp-112残基在该信号传导过程中起至关重要的作用.基于理论模拟和试验结果我们推测Ca2+离子诱导恢复蛋白的构象转变是一个两步过程.在该细胞信号Ca2+离子与恢复蛋白耦合过程中,EF-3和Ca2+耦合作用触发恢复蛋白构象转变,而EF-2和Ca2+的耦合作用起续航作用,促使变构过程完成.更多还原

【Abstract】 Recoverin is an important branch of neuronal calcium sensor.To clarify the coupling/decoupling interaction mechanism between EF-hands and Ca2+,a series of constant force pulling and constant velocity pulling non-equilibrium molecular dynamics simulations were performed by using a steered molecular dynamics method.The results show that,among the residues in the EF-2 and EF-3 loop motifs,the orders of chelation abilities are Asn-76<Thr-80<Glu-85<Asp-74<Asp-78 and Thr-116<Glu-121<Asp-110< Asn-114<Asp-112,respectively.The coupling interaction between EF-3 and Ca2+ is more powerful than that between EF-2 and Ca2+.The residues of Asp-78 and Asp-112 in the EF-hand loops play vital roles in the conformational transition involving signal transduction.According to the theoretical simulation and experimental results,it is safe to make the conclusion that the Ca2+-recoverin allostery is a two-step process.In the cell signal process of Ca2+ coupling with recoverin,the interaction of Ca2+ with EF-3 triggers the conformational transition of recoverin,whereas it is carried over by Ca2+ interacting with EF-2,which makes the transition completely.更多还原