In order to illustrate the ion transport mechanism of chloride channel (ClC) protein, a type of ClC protein, ClC-ec1, from Escherichia coli is embedded into an explicit membranewater system by using software VMD. Then a parallel molecular dynamics (MD) simulation is employed to equilibrate the ClC-ec1 structure for 27.5 ns at temperature 298.15 K. Based on this equilibrated structure, we compute the channel geometric size variation and electrostatic potential distribution along the channel. Meanwhile, Cl^- transport process is simulated using oriented random walk method under variable external potential. The simulation result shows that Cl^- transport velocity depends on the width of the narrowest channel region. Mutation of negative glutamate E148 can produce positive potential, which is beneficial for Cl^- transport, around external Cl^- binding region in the channel. The simulated current-voltage curves about Cl^- transporting in ClC-ec1 protein agree with Jayaram’s experimental results.

中文翻译：

---

复杂静电势下ClC型通道蛋白的离子迁移机理

为了说明氯离子通道蛋白（ClC）的离子迁移机理，使用VMD软件将一种来自大肠杆菌的ClC蛋白ClC-ec1嵌入到明确的膜水系统中。然后采用平行分子动力学（MD）模拟在298.15 K的温度下平衡ClC-ec1结构27.5 ns。基于此平衡结构，我们计算出通道的几何尺寸变化和沿通道的静电势分布。同时，氯^-运输过程中使用下可变外势导向的随机游走方法模拟。仿真结果表明，氯^-传输速度取决于最窄通道区域的宽度。负谷氨酸E148的突变可以产生正的电位，这是有益的氯^-运输，围绕外部氯^-在通道结合区。关于氯的模拟电流-电压曲线^-在CLC-EC1蛋白质运送同意贾亚拉姆的实验结果。