Structure of a slow CLC Cl⁻/H+ antiporter from a cyanobacterium.

ABSTRACT: X-ray crystal structures have been previously determined for three CLC-type transporter homologues, but the absolute unitary transport rate is known for only one of these. The Escherichia coli Cl(-)/H(+) antiporter (EC) moves ∼2000 Cl(-) ions/s, an exceptionally high rate among membrane-transport proteins. It is not known whether such rapid turnover is characteristic of ClCs in general or if the E. coli homologue represents a functional outlier. Here, we characterize a CLC Cl(-)/H(+) antiporter from the cyanobacterium Synechocystis sp. PCC6803 (SY) and determine its crystal structure at 3.2 Å resolution. The structure of SY is nearly identical to that of EC, with all residues involved in Cl(-) binding and proton coupling structurally similar to their equivalents in EC. SY actively pumps pr

SUBMITTER: Jayaram H 

PROVIDER: S-EPMC3164822 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature