Atomic-level characterization of transport cycle thermodynamics in the glycerol-3-phosphate:phosphate antiporter.

ABSTRACT: Membrane transporters actively translocate their substrate by undergoing large-scale structural transitions between inward- (IF) and outward-facing (OF) states ('alternating-access' mechanism). Despite extensive structural studies, atomic-level mechanistic details of such structural transitions, and as importantly, their coupling to chemical events supplying the energy, remain amongst the most elusive aspects of the function of these proteins. Here we present a quantitative, atomic-level description of the functional thermodynamic cycle for the glycerol-3-phosphate:phosphate antiporter GlpT by using a novel approach in reconstructing the free energy landscape governing the IF↔OF transition along a cyclic transition pathway involving both apo and substrate-bound states. Our results provide

SUBMITTER: Moradi M 

PROVIDER: S-EPMC4598623 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature