Hydrophobic gating in ion channels.
Hydrophobic gating in ion channels.
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DOI：
10.1016/j.jmb.2014.07.030
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发表时间：
2015-01-16
影响因子：
5.6
通讯作者：
Tucker SJ
中科院分区：
文献类型：
--
作者：
Aryal P;Sansom MS;Tucker SJ
生物离子通道是纳米级的跨膜孔。当水和离子被封闭在亚纳米疏水孔的狭窄范围内时，它们表现出从宏观描述中不明显的行为。在这种纳米级水平上，疏水孔的衬里和水之间的不利相互作用可能导致液体-蒸气振荡。所得到的瞬态蒸气状态是“去湿的”，即在全部或部分孔内有效地没有水分子，从而导致对离子传导的能量屏障。这个过程被称为“疏水门控”，首先在模型纳米孔的分子动力学模拟中观察到，其中疏水门控的基本原理（即直径，极性或跨膜电压的变化）现已得到广泛验证。计算，结构和功能的研究表明，生物离子通道也可以利用疏水门控来调节其孔内的离子流。在这里，我们回顾了这一过程的证据，并提出这种不寻常的行为的水代表了一个越来越重要的元素，在理解离子通道的结构和功能之间的关系。
Biological ion channels are nanoscale transmembrane pores. When water and ions are enclosed within the narrow confines of a sub-nanometer hydrophobic pore, they exhibit behavior not evident from macroscopic descriptions. At this nanoscopic level, the unfavorable interaction between the lining of a hydrophobic pore and water may lead to liquid-vapor oscillations. The resultant transient vapor state is ‘dewetted’ i.e. effectively devoid of water molecules within all, or part of the pore, thus leading to an energetic barrier to ion conduction. This process, termed ‘hydrophobic gating’, was first observed in molecular dynamics simulations of model nanopores, where the principles underlying hydrophobic gating (i.e. changes in diameter, polarity, or transmembrane voltage) have now been extensively validated. Computational, structural and functional studies now indicate that biological ion channels may also exploit hydrophobic gating to regulate ion flow within their pores. Here we review the evidence for this process, and propose that this unusual behavior of water represents an increasingly important element in understanding the relationship between ion channel structure and function.