Protein Domain : HTH-type transcriptional regulator BlaA, PBP2 domain IPR037422

Type	Domain
Description	This entry represents the C-terminal substrate binding domain of LysR-type transcriptional regulator BlaA, which is involved in control of the expression of beta-lactamase genes, blaA and blaB. Beta-lactamases are responsible for bacterial resistance to beta-lactam antibiotics such as penicillins. The blaA gene is located just upstream of blaB in the opposite direction and regulates the expression of the blaB. BlaA also negatively auto-regulates the expression of its own gene, blaA. BlaA (a constitutive class A penicllinase) belongs to the LysR family of transcriptional regulators, whereas BlaB (an inducible class C cephalosporinase or AmpC) can be referred to as a penicillin binding protein but it does not act as a beta-lactamase [ ]. The topology of this substrate-binding domain is most similar to that of the type 2 periplasmic binding proteins (PBP2).The PBP2 are responsible for the uptake of a variety of substrates such as phosphate, sulfate, polysaccharides, lysine/arginine/ornithine, and histidine. The PBP2 bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. After binding their specific ligand with high affinity, they can interact with a cognate membrane transport complex comprised of two integral membrane domains and two cytoplasmically located ATPase domains. This interaction triggers the ligand translocation across the cytoplasmic membrane energized by ATP hydrolysis. Besides transport proteins, the PBP2 superfamily includes the substrate- binding domains from ionotropic glutamate receptors, LysR-like transcriptional regulators, and unorthodox sensor proteins involved in signal transduction [ , , ].
Short Name	BlaA_PBP2