An ion gating mechanism of gastric H,K-ATPase based on molecular dynamics simulations.

ABSTRACT: Gastric H,K-ATPase is an electroneutral transmembrane pump that moves protons from the cytoplasm of the parietal cell into the gastric lumen in exchange for potassium ions. The mechanism of transport against the established electrochemical gradients includes intermediate conformations in which the transferred ions are trapped (occluded) within the membrane domain of the pump. The pump cycle involves switching between the E1 and E2P states. Molecular dynamics simulations on homology models of the E2P and E1 states were performed to investigate the mechanism of K(+) movement in this enzyme. We performed separate E2P simulations with one K(+) in the luminal channel, one K(+) ion in the occlusion site, two K(+) ions in the occlusion site, and targeted molecular dynamics from E2P to E1 with two

SUBMITTER: Law RJ 

PROVIDER: S-EPMC2527272 | biostudies-literature | 2008 Sep

REPOSITORIES: biostudies-literature