Brownian dynamics simulation of electrical properties of KcsA potassium ion channel

Abstract

As a regulator of cation activity in living cells, KcsA (K+ Conduction and Selectivity Architecture) potassium channel plays an important role in the depolarization and repolarization of nerve cell action potential. In this paper, Brownian Dynamics (BD) method is used to simulate the electrical characteristics of the actual KcsA potassium channel systematically. The PMF of ions in the channel under electrostatic field, the current-voltage characteristic curve of symmetric solution and asymmetric solution, the ion concentration distribution curve in the axial direction of the channel, and the conduction-concentration curve are obtained. The results showed that the SF region of KcsA potassium ion channel blocked the passage of Cl- basically, showing a special selection characteristic of the passage of K+; Its current-voltage curve basically presents a linear distribution, and the conductivity-concentration curve presents a trend of first increasing and then flattening. The basic law is consistent with the experimental phenomenon. In addition, the influence of the specific intensity THz field on the channel K+ current is also simulated and analyzed. Compared with the electrostatic field of the same amplitude, the selected 0.6/1.2/5THz terahertz field can reduce the PMF by affecting the interaction potential energy between ion pairs, thereby increasing the K+ current. The research in this paper not only deepens the understanding of the regularity of KcsA potassium ion channels, but also provides a new idea for the study of other types of ion channels and the influence of terahertz field on the characteristics of ion channels.