Molecular dynamics study of the KcsA potassium channel

被引:146
作者
Allen, TW
Kuyucak, S
Chung, SH
机构
[1] Australian Natl Univ, Dept Chem, Prot Dynam Unit, Canberra, ACT 0200, Australia
[2] Australian Natl Univ, Dept Theoret Phys, Res Sch Phys Sci, Canberra, ACT 0200, Australia
基金
英国医学研究理事会; 澳大利亚研究理事会;
关键词
D O I
10.1016/S0006-3495(99)77086-4
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
The structural, dynamical, and thermodynamic properties of a model potassium channel are studied using molecular dynamics simulations, We use the recently unveiled protein structure for the KcsA potassium channel from Streptomyces lividans. Total and free energy profiles of potassium and sodium ions reveal a considerable preference for the larger potassium ions. The selectivity of the channel arises from its ability to completely solvate the potassium ions, but not the smaller sodium ions. Self-diffusion of water within the narrow selectivity filter is found to be reduced by an order of magnitude from bulk levels, whereas the wider hydrophobic section of the pore maintains near-bulk self-diffusion. Simulations examining multiple ion configurations suggest a two-ion channel. ion diffusion is found to be reduced to similar to 1/3 of bulk diffusion within the selectivity filter. The reduced ion mobility does not hinder the passage of ions, as permeation appears to be driven by Coulomb repulsion within this multiple ion channel.
引用
收藏
页码:2502 / 2516
页数:15
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