Green M E, Lewis J
Department of Chemistry, City College, City University of New York, New York 10031.
Biophys J. 1991 Feb;59(2):419-26. doi: 10.1016/S0006-3495(91)82235-4.
A Monte Carlo simulation of water in a channel with charges suggests the existence of water in immobile, high density, essentially glasslike form near the charges. The channel model has a conical section with an opening through which water molecules can pass, at the narrow end of the cone, and a cylindrical section at the other end. When the charges are placed near the narrow section of the model, the "glass" effectively blocks the channel; with the charges removed, the channel opens. The effect can be determined from the rate of passage of the water molecules through the pore, from the average orientation of the water molecule, and from distortion of the distribution of molecules. In the simulations carried out to date, no external ions have been considered. In addition to the energy, the Helmholtz free energy has been calculated.
对带有电荷的通道中的水进行的蒙特卡洛模拟表明，在电荷附近存在呈固定、高密度、本质上类似玻璃状形式的水。通道模型有一个在圆锥体窄端带有水分子可通过开口的圆锥部分，以及在另一端的圆柱部分。当电荷置于模型的窄部附近时，“玻璃”有效地阻塞通道；去除电荷后，通道打开。这种效应可根据水分子通过孔隙的速率、水分子的平均取向以及分子分布的畸变来确定。在迄今为止进行的模拟中，未考虑外部离子。除了能量之外，还计算了亥姆霍兹自由能。
