The complicated patterns of the single-channel currents in potassium ion channel KcsA are governed by the structural variability of the selectivity filter. A comparative analysis of the dynamics of the wild type KcsA channel and several of its mutants showing different conducting patterns was performed. A strongly correlated dynamical network of interacting residues is found to play a key role in regulating the state of the wild type channel. The network is centered on the aspartate D80 which plays the role of a hub by strong interacting via hydrogen bonds with residues E71, R64, R89, and W67. Residue D80 also affects the selectivity filter via its backbones. This network further compromises ions and water molecules located inside the channel that results in the mutual influence: the permeation depends on the configuration of residues in the network, and the dynamics of network's residues depends on locations of ions and water molecules inside the selectivity filter. Some features of the network provide a further understanding of experimental results describing the KcsA activity. In particular, the necessity of anionic lipids to be present for functioning the channel is explained by the interaction between the lipids and the arginine residues R64 and R89 that prevents destabilizing the structure of the selectivity filter.

中文翻译：

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揭示控制 KcsA 离子通道中钾渗透的强相关残基动态网络


钾离子通道 KcsA 中单通道电流的复杂模式由选择性滤波器的结构可变性控制。对野生型 KcsA 通道及其几种表现出不同传导模式的突变体的动力学进行了比较分析。发现相互作用残基的强相关动态网络在调节野生型通道的状态中发挥关键作用。该网络以天冬氨酸 D80 为中心，通过氢键与残基 E71、R64、R89 和 W67 发生强相互作用，发挥枢纽的作用。残留物 D80 还通过其主链影响选择性过滤器。该网络进一步损害了通道内的离子和水分子，导致相互影响：渗透取决于网络中残留物的配置，而网络残留物的动态取决于选择性过滤器内离子和水分子的位置。网络的一些特征提供了对描述 KcsA 活动的实验结果的进一步理解。特别地，存在阴离子脂质以发挥通道功能的必要性可以通过脂质与精氨酸残基R64和R89之间的相互作用来解释，该相互作用防止选择性过滤器的结构不稳定。