Last of the multidrug transporters

Abstract

Proteins that pump a wide range of toxic compounds out of cells are ubiquitous in nature, but crystal structures for one family of these transporters have remained elusive. Until now. See Letter p.991 Transporter proteins from the MATE (multidrug and toxic compound extrusion) family are involved in metabolite transport in plants and in multidrug resistance in bacteria and mammals. MATE transporters were the only remaining class of multidrug resistance transporter whose structure was not known. The X-ray structure of a prototypical MATE protein, NorM from Vibrio cholerae, has now been determined to 3.65 A resolution, revealing a protein topology distinct from other membrane-protein structures solved to date. The structure is in an 'outward-facing' conformation, with a cation-binding site in close proximity to residues previously deemed critical for transport.