New insights into the structure and oligomeric state of the bacterial multidrug transporter EmrE: an unusual asymmetric homo‐dimer
- 5 March 2004
- journal article
- Published by Wiley in FEBS Letters
- Vol. 564 (3) , 234-238
- https://doi.org/10.1016/s0014-5793(04)00228-5
Abstract
EmrE is a small multidrug transporter that contains 110 amino acid residues that form four transmembrane α‐helices. The three‐dimensional structure of EmrE has been determined from two‐dimensional crystals by electron cryo‐microscopy. EmrE is an asymmetric homo‐dimer with one substrate molecule bound in a chamber accessible laterally from one leaflet of the lipid bilayer. Evidence from substrate binding analyses and analytical ultracentrifugation of detergent‐solubilised EmrE shows that the minimum functional unit for substrate binding is a dimer. However, it is possible that EmrE exists as a tetramer in vivo and plausible models are suggested based upon analyses of two‐dimensional crystals.Keywords
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