InterPro domain: IPR001638

Bacterial high affinity transport systems are involved in active transport of solutes across the cytoplasmic membrane. Most of the bacterial ABC (ATP-binding cassette) importers are composed of one or two transmembrane permease proteins, one or two nucleotide-binding proteins and a highly specific periplasmic solute-binding protein. In Gram-negative bacteria the solute-binding proteins are dissolved in the periplasm, while in archaea and Gram-positive bacteria, their solute-binding proteins are membrane-anchored lipoproteins [ 1 , 2 ].

On the basis of sequence similarities, the vast majority of these solute-binding proteins can be grouped [ 3 ] into eight families or clusters, which generally correlate with the nature of the solute bound.

This entry represents a domain found in the solute-binding protein family 3 members from Gram-positive bacteria, Gram-negative bacteria and archaea. This domain can also be found in the N-terminal of the membrane-bound lytic murein transglycosylase F (MltF) protein. MltF is a murein-degrading enzyme that degrades murein glycan strands and insoluble, high-molecular weight murein sacculi, with the concomitant formation of a 1,6-anhydromuramoyl product [ 4 ].

Familiy 3 members include:

• Histidine-binding protein (gene hisJ) of Escherichia coli and related bacteria. An homologous lipoprotein exists in Neisseria gonorrhoeae.
• Lysine/arginine/ornithine-binding proteins (LAO) (gene argT) of Escherichia coli and related bacteria are involved in the same transport system than hisJ. Both solute-binding proteins interact with a common membrane-bound receptor hisP of the binding protein dependent transport system HisQMP.
• Glutamine-binding proteins (gene glnH) of Escherichia coli and Bacillus stearothermophilus.
• Glutamate-binding protein (gene gluB) of Corynebacterium glutamicum.
• Arginine-binding proteins artI and artJ of Escherichia coli.
• Nopaline-binding protein (gene nocT) from Agrobacterium tumefaciens.
• Octopine-binding protein (gene occT) from Agrobacterium tumefaciens.
• Major cell-binding factor (CBF1) (gene: peb1A) from Campylobacter jejuni.
• Bacteroides nodosus protein aabA.
• Cyclohexadienyl/arogenate dehydratase of Pseudomonas aeruginosa, a periplasmic enzyme which forms an alternative pathway for phenylalanine biosynthesis.
• Escherichia coli protein fliY.
• Vibrio harveyi protein patH.
• Escherichia coli hypothetical protein ydhW.
• Bacillus subtilis hypothetical protein yckB.
• Bacillus subtilis hypothetical protein yckK.

1. Sequence relationships between integral inner membrane proteins of binding protein-dependent transport systems: evolution by recurrent gene duplications. Protein Sci. 3, 325-44
2. Characterization of a Pseudomonas putida ABC transporter (AatJMQP) required for acidic amino acid uptake: biochemical properties and regulation by the Aau two-component system. Microbiology (Reading, Engl.) 154, 797-809
3. Structural, functional, and evolutionary relationships among extracellular solute-binding receptors of bacteria. Microbiol. Rev. 57, 320-46
4. The C-terminal domain of Escherichia coli YfhD functions as a lytic transglycosylase. J. Biol. Chem. 283, 8363-73