InterPro domain: IPR005667

Bacterial binding protein-dependent transport systems [ 1 , 2 ] are multicomponent systems typically composed of a periplasmic substrate-binding protein, one or two reciprocally homologous integral inner-membrane proteins and one or two peripheral membrane ATP-binding proteins that couple energy to the active transport system. The integral inner-membrane proteins translocate the substrate across the membrane. It has been shown [ 3 , 4 ] that most of these proteins contain a conserved region located about 80 to 100 residues from their C-terminal extremity. This region seems to be located in a cytoplasmic loop between two transmembrane domains [ 5 ]. Apart from the conserved region, the sequence of these proteins is quite divergent, and they have a variable number of transmembrane helices.

This entry describes a subfamily of both CysT and CysW, paralogous and generally tandemly encoded permease proteins of the sulphate ABC transporter [ 6 , 7 ].

1. Bacterial periplasmic transport systems: structure, mechanism, and evolution. Annu. Rev. Biochem. 55, 397-425
2. Binding protein-dependent transport systems. J. Bioenerg. Biomembr. 22, 571-92
3. Sequence of gene malG in E. coli K12: homologies between integral membrane components from binding protein-dependent transport systems. EMBO J. 4, 2287-93
4. Bacterial binding protein-dependent permeases: characterization of distinctive signatures for functionally related integral cytoplasmic membrane proteins. Mol. Microbiol. 12, 993-1004
5. Membrane topology of the integral membrane components, OppB and OppC, of the oligopeptide permease of Salmonella typhimurium. Mol. Microbiol. 6, 47-57
6. Sulfate and thiosulfate transport in Escherichia coli K-12: nucleotide sequence and expression of the cysTWAM gene cluster. J. Bacteriol. 172, 3351-7
7. Sulfate and thiosulfate transport in Escherichia coli K-12: evidence for a functional overlapping of sulfate- and thiosulfate-binding proteins. J. Bacteriol. 177, 4134-6