Structural Basis for the Function of the C-Terminal Proton Release Pathway in the Calcium Pump.

ABSTRACT: The calcium pump (sarco/endoplasmic reticulum Ca2+-ATPase, SERCA) plays a major role in calcium homeostasis in muscle cells by clearing cytosolic Ca2+ during muscle relaxation. Active Ca2+ transport by SERCA involves the structural transition from a low-Ca2+ affinity E2 state toward a high-Ca2+ affinity E1 state of the pump. This structural transition is accompanied by the countertransport of protons to stabilize the negative charge and maintain the structural integrity of the transport sites and partially compensate for the positive charges of the two Ca2+ ions passing through the membrane. X-ray crystallography studies have suggested that a hydrated pore located at the C-terminal domain of SERCA serves as a conduit for proton countertransport, but the existence and function of this pathw

SUBMITTER: Espinoza-Fonseca LM 

PROVIDER: S-EPMC8037123 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature