Coulomb blockade model of permeation and selectivity in biological ion channels
Coulomb blockade model of permeation and selectivity in biological ion channels
复制标题
DOI：
10.1088/1367-2630/17/8/083021
复制
发表时间：
2015-08-11
影响因子：
3.3
通讯作者：
Eisenberg, R. S.
中科院分区：
文献类型：
--
作者：
Kaufman, I. kh;McClintock, P. V. E.;Eisenberg, R. S.
生物离子通道是一种蛋白质纳米管，嵌入并穿过细胞的双脂膜。在生理上，它们是至关重要的，因为它们允许离子快速有效地进出细胞，尽管是以高度选择性的方式。在这里，我们表明，钙/钠离子通道的传导和选择性可以描述在离子库仑阻塞在一个简化的静电和布朗动力学模型的通道。库仑阻塞现象源于电荷的离散性、强静电相互作用和静电排斥原理。该模型预测了一个周期性模式的钙离子传导与固定电荷Q（f）的选择性过滤器（导带）的周期等于离子电荷。因此，它提供了一些观察到的和模拟的传导和价选择性现象，包括异常摩尔分数效应和钙导带的临时解释。离子库仑阻塞和共振传导类似于量子点中的电子库仑阻塞和共振隧穿。相同的考虑也可以适用于其他种类的通道，以及带电的人工纳米孔。
Biological ion channels are protein nanotubes embedded in, and passing through, the bilipid membranes of cells. Physiologically, they are of crucial importance in that they allow ions to pass into and out of cells, fast and efficiently, though in a highly selective way. Here we show that the conduction and selectivity of calcium/sodium ion channels can be described in terms of ionic Coulomb blockade in a simplified electrostatic and Brownian dynamics model of the channel. The Coulomb blockade phenomenon arises from the discreteness of electrical charge, the strong electrostatic interaction, and an electrostatic exclusion principle. The model predicts a periodic pattern of Ca2+ conduction versus the fixed charge Q(f) at the selectivity filter (conduction bands) with a period equal to the ionic charge. It thus provides provisional explanations of some observed and modelled conduction and valence selectivity phenomena, including the anomalous mole fraction effect and the calcium conduction bands. Ionic Coulomb blockade and resonant conduction are similar to electronic Coulomb blockade and resonant tunnelling in quantum dots. The same considerations may also be applicable to other kinds of channel, as well as to charged artificial nanopores.