InterPro domain: IPR044085

This entry represents the PBP (periplasmic binding protein) domain found in a group of glucose/galactose-binding proteins, including MglB (a D-galactose-binding periplasmic protein) from E. coli [ 1 ]. They belong to the periplasmic binding protein superfamily which consists of two alpha/beta globular domains connected by a three-stranded hinge. This Venus flytrap-like domain undergoes transition from an open to a closed conformational state upon ligand binding [ 2 , 3 ]. Moreover, this group of proteins are homologous to the ligand-binding domain of eukaryotic receptors such as glutamate receptor (GluR) and DNA-binding transcriptional repressors such as LacI and GalR [ 4 , 5 ].

1. Sequence of the mglB gene from Escherichia coli K12: comparison of wild-type and mutant galactose chemoreceptors. Mol. Gen. Genet. 208, 247-53
2. Amino acid recognition by Venus flytrap domains is encoded in an 8-residue motif. Biopolymers 80, 357-66
3. The Venus flytrap of periplasmic binding proteins: an ancient protein module present in multiple drug receptors. AAPS PharmSci 1, E2
4. Parallel evolution of ligand specificity between LacI/GalR family repressors and periplasmic sugar-binding proteins. Mol. Biol. Evol. 20, 267-77
5. Phylogenetic, structural and functional analyses of the LacI-GalR family of bacterial transcription factors. FEBS Lett. 377, 98-102