Proton Countertransport and Coupled Gating in the Sarcoplasmic Reticulum Calcium Pump.

ABSTRACT: The calcium pump of the sarcoplasmic reticulum (SERCA) is an ATP-driven active transporter of Ca²⁺ ions that functions via an "alternating-access" cycle mechanism. In each cycle, SERCA transports two Ca²⁺ ions toward the lumen of the sarcoplasmic reticulum and two to three protons to the cytoplasm. How the latter conformational transition is coupled to cytoplasmic release of protons remains poorly understood. The present computational study shows how the mechanism of proton countertransport is coupled to the alternating access gating process in SERCA. Molecular dynamics simulation trajectories are generated starting from a series of configurations taken along the E2 to E1 transition pathway determined by the string method with swarms-of-trajectories. Simulations of di

SUBMITTER: Rui H 

PROVIDER: S-EPMC6413324 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature