Molecular Basis for Differential Anion Binding and Proton Coupling in the Cl(-)/H(+) Exchanger ClC-ec1.

ABSTRACT: Cl–/H+ transporters of the CLC superfamily form a ubiquitous class of membrane proteins that catalyze stoichiometrically coupled exchange of Cl– and H+ across biological membranes. CLC transporters exchange H+ for halides and certain polyatomic anions, but exclude cations, F–, and larger physiological anions, such as PO43– and SO42–. Despite comparable transport rates of different anions, the H+ coupling in CLC transporters varies significantly depending on the chemical nature of the transported anion. Although the molecular mechanism of exchange remains unknown, studies on bacterial ClC-ec1 transporter revealed that Cl– binding to the central anion-binding site (Scen) is crucial for the anion-coupled H+ transport. Here, we show that Cl–, F–, NO3–, and SCN– display distinct binding coordin

SUBMITTER: Jiang T 

PROVIDER: S-EPMC4898471 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature