The C-terminal substrate domain of LysR-type GcdR, TrPI, HvR and beta-lactamase regulators, and that of other closely related homologs; contains the type 2 periplasmic binding fold.
This CD includes the C-terminal substrate domain of LysR-type transcriptional regulators involved in controlling the expression of glutaryl-CoA dehydrogenase (GcdH), S-adenosyl-L-homocysteine hydrolase, cell division protein FtsW, tryptophan synthase, and beta-lactamase. The structural topology of this substrate-binding domain is most similar to that of the type 2 periplasmic binding proteins (PBP2), which 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.
Jiyao W et al.(2023). "The conserved domain database in 2023.",