Substrate recognition and proton coupling by a bacterial member of solute carrier family 17.

The solute carrier 17 family transports diverse organic anions using two distinct modes of coupling to a source of energy. Transporters that package glutamate and nucleotide into secretory vesicles for regulated release by exocytosis are driven by membrane potential but subject to allosteric regulation by H and Cl. Other solute carrier 17 members including the lysosomal sialic acid exporter couple the flux of organic anion to cotransport of H.