InterPro: IPR011852 TRAP transporter solute receptor, TAXI family

This family is one of at least three major families of extracytoplasmic solute receptor (ESR) for TRAP (Tripartite ATP-independent Periplasmic Transporter) transporters. The others are the DctP (IPR004682) and SmoM (IPR004682) families. These transporters are secondary (driven by an ion gradient) but composed of three polypeptides, although in some species the 4-TM and 12-TM integral membrane proteins are fused. Substrates for this transporter family are not fully characterised but, besides C4 dicarboxylates, may include mannitol and other compounds [1].