ATP-dependent Conformational Changes Trigger Substrate Capture and Release by an ECF-type Biotin Transporter.

ABSTRACT: Energy-coupling factor (ECF) transporters for vitamins and metal ions in prokaryotes consist of two ATP-binding cassette-type ATPases, a substrate-specific transmembrane protein (S component) and a transmembrane protein (T component) that physically interacts with the ATPases and the S component. The mechanism of ECF transporters was analyzed upon reconstitution of a bacterial biotin transporter into phospholipid bilayer nanodiscs. ATPase activity was not stimulated by biotin and was only moderately reduced by vanadate. A non-hydrolyzable ATP analog was a competitive inhibitor. As evidenced by cross-linking of monocysteine variants and by site-specific spin labeling of the Q-helix followed by EPR-based interspin distance analyses, closure and reopening of the ATPase dimer (BioM2) was a con

SUBMITTER: Finkenwirth F 

PROVIDER: S-EPMC4505438 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature