The cavity and pore helices the KcsA K+ channel:: Electrostatic stabilization of monovalent cations
The cavity and pore helices the KcsA K+ channel:: Electrostatic stabilization of monovalent cations
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DOI：
10.1126/science.285.5424.100
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发表时间：
1999-07-02
期刊：
影响因子：
56.9
通讯作者：
MacKinnon, R
中科院分区：
文献类型：
--
作者：
Roux, B;MacKinnon, R
通过求解有限差分泊松方程，分析了来自淡紫灰链霉菌的钾离子通道（KcsA K⁺通道）中中央腔和孔α螺旋的静电影响。该腔和螺旋克服了膜的去稳定作用，并使阳离子在膜中心稳定。由于低介电膜环境，与水溶性蛋白质所描述的情况相比，孔螺旋的静电效应较大。离子自能和螺旋静电场的共同作用导致了对充满水的腔中单价阳离子的选择性。因此，K⁺通道利用简单的静电原理解决了细胞膜脂质双层使离子不稳定的基本问题。
The electrostatic influence of the central cavity and pore alpha helices in the potassium ion channel from Streptomyces lividans (KcsA K+ channel) was analyzed by solving the finite difference Poisson equation. The cavity and helices overcome the destabilizing influence of the membrane and stabilize a cation at the membrane center. The electrostatic effect of the pore helices is large compared to that described for water-soluble proteins because of the low dielectric membrane environment. The combined contributions of the ion self-energy and the helix electrostatic field give rise to selectivity for monovalent cations in the water-filled cavity. Thus, the K+ channel uses simple electrostatic principles to solve the fundamental problem of ion destabilization by the cell membrane lipid bilayer.