Exterior site occupancy infers chloride-induced proton gating in a prokaryotic homolog of the ClC chloride channel.

ABSTRACT: The ClC family of anion channels mediates the efficient, selective permeation of Cl(-) across the biological membranes of living cells under the driving force of an electrochemical gradient. In some eukaryotes, these channels are known to exhibit a unique gating mechanism, which appears to be triggered by the permeant Cl(-) anion. We infer details of this gating mechanism by studying the free energetics of Cl(-) occupancy in the pore of a prokaryotic ClC homolog. These free energetics were gleaned from 30 ns of molecular dynamics simulation on an approximately 133,000-atom system consisting of a hydrated membrane embedded StClC transporter. The binding sites for Cl(-) in the transporter were determined for the cases where the putative gating residue, Glu(148), was protonated and unprotonat

SUBMITTER: Bostick DL 

PROVIDER: S-EPMC1304573 | biostudies-literature | 2004 Sep

REPOSITORIES: biostudies-literature