Structures of FolT in substrate-bound and substrate-released conformations reveal a gating mechanism for ECF transporters.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26198469.
- Also identified by DOI 10.1038/ncomms8661 and PMC identifier 4525288.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Energy-coupling factor (ECF) transporters are a new family of ABC transporters that consist of four subunits, two cytoplasmic ATPases EcfA and EcfA' and two transmembrane proteins namely EcfS for substrate-specific binding and EcfT for energy coupling. Here, we report the 3.2-Å resolution crystal structure of the EcfS protein of a folate ECF transporter from Enterococcus faecalis-EfFolT, a close homologue of FolT from Lactobacillus brevis-LbFolT. Structural and biochemical analyses reveal the residues constituting the folate-binding pocket and determining the substrate-binding specificity. Structural comparison of the folate-bound EfFolT with the folate-free LbFolT contained in the holotransporter complex discloses significant conformational change at the L1 loop, and reveals a gating mechanism of ECF transporters in which the L1 loop of EcfS acts as a gate in the substrate binding and release.
Medical subject headings
- Bacterial Proteins
- Enterococcus faecalis