In this study we examined the influence of a transmembrane voltage on the hydrophobic gating of nanopores using molecular dynamics simulations. We observed electric field induced wetting of a hydrophobic gate in a biologically inspired model nanopore based on the 5-HT3 receptor in its closed state, with a field of at least ∼100 mV nm−1 was required to hydrate the pore. We also found an unequal distribution of charged residues can generate an electric field intrinsic to the nanopore which, depending on its orientation, can alter the effect of the external field, thus making the wetting response asymmetric. This wetting response could be described by a simple model based on water surface tension, the volumetric energy contribution of the electric field, and the influence of charged amino acids lining the pore. Finally, the electric field response was used to determine time constants characterising the phase transitions of water confined within the nanopore, revealing liquid-vapour oscillations on a time scale of ~5 ns. This time scale was largely independent of the water model employed and was similar for different sized pores representative of the open and closed states of the pore. Furthermore, our finding that the threshold voltage required for hydrating a hydrophobic gate depends on the orientation of the electric field provides an attractive perspective for the design of rectifying artificial nanopores.

中文翻译：

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电场诱导的基于5-HT3受体通道的模型纳米孔中疏水门的润湿

在这项研究中，我们使用分子动力学模拟研究了跨膜电压对纳米孔疏水门控的影响。我们观察到电场激发的基于5-HT3受体处于闭合状态的生物学启发的模型纳米孔中疏水门的润湿，需要至少约100 mV nm-1的电场来水合孔隙。我们还发现，带电残基的不均匀分布会产生纳米孔固有的电场，该电场取决于纳米孔的方向，可能会改变外部电场的作用，从而使润湿响应不对称。可以通过基于水表面张力，电场的体积能量贡献以及带电氨基酸对孔隙排列的简单模型描述这种润湿响应。最后，电场响应被用来确定表征在纳米孔内的水的相变特征的时间常数，揭示了〜5 ns时间尺度上的液-气振荡。该时间尺度在很大程度上与所采用的水模型无关，并且对于代表孔的打开和闭合状态的不同尺寸的孔而言，时间尺度相似。此外，我们发现水合疏水性栅极所需的阈值电压取决于电场的方向的发现为整流人工纳米孔的设计提供了诱人的视角。该时间尺度在很大程度上与所采用的水模型无关，并且对于代表孔的打开和闭合状态的不同尺寸的孔而言，时间尺度相似。此外，我们发现水合疏水性栅极所需的阈值电压取决于电场的方向的发现为整流人工纳米孔的设计提供了诱人的视角。该时间尺度在很大程度上与所采用的水模型无关，并且对于代表孔的打开和闭合状态的不同尺寸的孔而言，时间尺度相似。此外，我们发现水合疏水性栅极所需的阈值电压取决于电场的方向的发现为整流人工纳米孔的设计提供了诱人的视角。