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Substrate binding domain of 2'-hydroxybiphenyl-2-sulfinate desulfinase, a member of the type 2 periplasmic binding fold superfamily. This subfamily includes DszB, which converts 2'-hydroxybiphenyl-2-sulfinate to 2-hydroxybiphenyl and sulfinate at the rate-limiting step of the microbial dibenzothiophene desulfurization pathway. The overall fold of DszB is highly similar to those of periplasmic substrate-binding proteins that serve as initial receptors in the ABC transport of bicarbonate, nitrate, taurine, or a wide range of aliphatic sulfonates. After binding their ligand with high affinity, they 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. The DszB protein belongs to the PBP2 superfamily of periplasmic binding proteins that differ in size and ligand specificity, but have similar tertiary structures consisting of two globular subdomains connected by a flexible hinge. They have been shown to bind their ligand in the cleft between these domains in a manner resembling a Venus flytrap. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",