Effect of external electric fields on the potential energy profile of K+ ions in selective filter of the KcsA potassium channel

Abstract

In this study, the potential energy profile of potassium ions in the selective filter part of a KcsA channel was investigated via the application of the molecular simulation method. For this purpose, using the molecular dynamics simulation, the effect of an applied electric field, either constant or oscillating, was studied on the dynamics of K ions in the filter. It was found that when the channel is exposed to a constant electric field of strength 0.03 V/nm, the ions experience a hopping motion. Furthermore, it was shown that the application of oscillating electric fields of 1 and 2.5 GHz, can increase the rigidity of the filter atomic bonds. By computing the potential energy of K ion in the filter, it was shown that the depth of the potential wells, corresponding to the filter sites, increased when an alternative field was applied. Therefore, exposing the channel to the GHz oscillating electric field could disturb the passing rate of ions through the filter, which in turn may affect the operation of these kinds of channels.