Microscopic origin of gating current fluctuations in a potassium channel voltage sensor.

ABSTRACT: Voltage-dependent ion channels open and close in response to changes in membrane electrical potential due to the motion of their voltage-sensing domains (VSDs). VSD charge displacements within the membrane electric field are observed in electrophysiology experiments as gating currents preceding ionic conduction. The elementary charge motions that give rise to the gating current cannot be observed directly, but appear as discrete current pulses that generate fluctuations in gating current measurements. Here we report direct observation of gating-charge displacements in an atomistic molecular dynamics simulation of the isolated VSD from the KvAP channel in a hydrated lipid bilayer on the timescale (10-μs) expected for elementary gating charge transitions. The results reveal that gating-charg

SUBMITTER: Freites JA 

PROVIDER: S-EPMC3368149 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature