Department of Chemistry, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Chem Phys. 2020 Sep 21;153(11):110901. doi: 10.1063/5.0017537.
Water is at the heart of almost all biological phenomena, without which no life that we know of would have been possible. It is a misleadingly complex liquid that exists in near coexistence with the vapor phase under ambient conditions. Confinement within a hydrophobic cavity can tip this balance enough to drive a cooperative dewetting transition. For a nanometer-scale pore, the dewetting transition leads to a stable dry state that is physically open but impermeable to ions. This phenomenon is often referred to as hydrophobic gating. Numerous transmembrane protein ion channels have now been observed to utilize hydrophobic gating in their activation and regulation. Here, we review recent theoretical, simulation, and experimental studies that together have started to establish the principles of hydrophobic gating and discuss how channels of various sizes, topologies, and biological functions can utilize these principles to control the thermodynamic properties of water within their interior pores for gating and regulation. Exciting opportunities remain in multiple areas, particularly on direct experimental detection of hydrophobic dewetting in biological channels and on understanding how the cell may control the hydrophobic gating in regulation of ion channels.
水是几乎所有生物现象的核心，没有水，我们所知的生命就不可能存在。它是一种具有误导性的复杂液体，在环境条件下几乎与气相共存。在疏水性空腔内的限制足以使这种平衡发生变化，从而导致协同去湿转变。对于纳米级的孔，去湿转变导致稳定的干燥状态，该状态在物理上是开放的，但对离子是不可渗透的。这种现象通常被称为疏水性门控。现在已经观察到许多跨膜蛋白离子通道利用疏水性门控来激活和调节。在这里，我们回顾了最近的理论、模拟和实验研究，这些研究共同开始建立疏水性门控的原理，并讨论了各种大小、拓扑和生物学功能的通道如何利用这些原理来控制其内部孔内水的热力学性质，以进行门控和调节。在多个领域仍有令人兴奋的机会，特别是在生物通道中疏水性去湿的直接实验检测以及了解细胞如何控制离子通道调节中的疏水性门控方面。
