Characterization of a novel transporter family that includes multiple Escherichia coli gluconate transporters and their homologues

The nucleotide sequences of seven Escherichia coli genes that encode members of the gluconate permease (GntP) family have recently become available. These genes include gntP, gntT, gntU, gntW, ORFf449, dsdX, and ORFo454. The deduced amino acid sequences of all seven E. coli genes are homologous to the gntP gene products from Bacillus subtilis and B. licheniformis as well as two additional gene products from Haemophilus influenzae. These 11 proteins are not demonstrably homologous to members of the major facilitator superfamily or other recognized permease families. Four of the E. coli gluconate transporter genes have been cloned and shown to encode gluconate transporters with apparent affinities ranging from 6 to 212 μM. These studies serve to characterize a novel family of bacterial permeases.