Electronic Polarization Leads to a Drier Dewetted State for Hydrophobic Gating in the Big Potassium Channel,The Journal of Physical Chemistry Letters

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Electronic Polarization Leads to a Drier Dewetted State for Hydrophobic Gating in the Big Potassium Channel
The Journal of Physical Chemistry Letters ( IF 4.8 ) Pub Date : 2024-07-15 , DOI: 10.1021/acs.jpclett.4c01359
Jiahua Deng ₁ , Qiang Cui _{1,

2,

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Affiliation

In the hydrophobic gating mechanism proposed for some ion channels, ion permeation is not blocked by the physical dimension of the channel pore but by its dewetted state which constitutes the energetic bottleneck. A major source of uncertainty in the mechanism is that the dewetted state was not observed in experiments and only probed in simulations using nonpolarizable force fields, which do not accurately represent the properties of confined water. Here we analyze hydration of the central cavity in the pore-gate domain of the Big Potassium channel using molecular dynamics and grand canonical Monte Carlo simulations with enhanced sampling techniques. Including polarization leads to a much drier dewetted state and a higher barrier for the transition to the wet state, suggesting more effective hydrophobic gating. The simulations also identify two backbone carbonyls at the bottom of the selectivity filter as good candidates for characterizing the dewetted state using infrared spectroscopies.

中文翻译：

电子极化导致大钾通道中疏水门控更干燥的去湿状态

在为某些离子通道提出的疏水门控机制中，离子渗透不是被通道孔的物理尺寸所阻碍，而是被构成能量瓶颈的去湿状态所阻碍。该机制不确定性的一个主要来源是，在实验中没有观察到去湿状态，仅在使用非极化力场的模拟中进行探测，这不能准确地代表承压水的特性。在这里，我们使用分子动力学和大正则蒙特卡罗模拟以及增强的采样技术来分析大钾通道孔门域中中央腔的水合作用。包括极化会导致更干燥的去湿状态以及向湿态转变的更高势垒，这表明疏水门控更有效。模拟还确定了选择性滤光片底部的两个主链羰基是使用红外光谱表征去湿状态的良好候选者。

更新日期：2024-07-15

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