Doklady Biochemistry and Biophysics ( IF 0.8 ) Pub Date : 2023-01-18 , DOI: 10.1134/s1607672922600245 Yu A Trofimov 1, 2 , A S Minakov 3 , N A Krylov 1, 4 , R G Efremov 1, 4, 5
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Abstract
The so-called “hydrophobic gating” is widely discussed as a putative mechanism to control water and ion conduction via ion channels. This effect can occur in narrow areas of the channels pore lined by non-polar residues. In the closed state of the channel, such regions may spontaneously transit to a dehydrated state to block water and ions transport without full pore occlusion. In the open state, the hydrophobic gate is wide enough to provide sustainable hydration and conduction. Apparently, the transport through the open hydrophobic gate may by facilitated by some polar residues that assist polar/charged substances to overcome the energy barrier created by nonpolar environment. In this work, we investigated the behavior of Na+ ions and their hydration shells in the open pore of the rat TRPV1 ion channel by molecular dynamics simulations. We show that polar protein groups coordinate water molecules in such a way as to restore the hydration shell of ions in the hydrophobic gate that ensures ion transport through the gate in a fully hydrated state.
中文翻译：
TRPV1 通道离子电导率的结构机制
摘要
所谓的“疏水门控”被广泛讨论为通过离子通道控制水和离子传导的推定机制。这种效应可以发生在由非极性残留物排列的通道孔隙的狭窄区域。在通道的关闭状态下，这些区域可能会自发地转变为脱水状态以阻止水和离子传输而不会完全堵塞孔隙。在打开状态下，疏水门足够宽以提供可持续的水合作用和传导。显然，一些极性残基可以促进通过开放疏水门的传输，这些极性残基有助于极性/带电物质克服非极性环境产生的能垒。在这项工作中，我们研究了 Na +的行为通过分子动力学模拟在大鼠 TRPV1 离子通道的开孔中离子及其水合壳。我们表明极性蛋白质基团以这样一种方式协调水分子，以恢复疏水门中离子的水合壳，确保离子在完全水合状态下通过门传输。
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