C-terminal catalytic domain of the oxygenase alpha subunit of Rieske-type non-heme iron aromatic ring-hydroxylating oxygenases
C-terminal catalytic domain of the oxygenase alpha subunit of Rieske-type non-heme iron aromatic ring-hydroxylating oxygenase (RHO) family. RHOs, also known as aromatic ring hydroxylating dioxygenases, utilize non-heme Fe(II) to catalyze the addition of hydroxyl groups to the aromatic ring, an initial step in the oxidative degradation of aromatic compounds. RHOs are composed of either two or three protein components, and are comprised of an electron transport chain (ETC), and an oxygenase. The ETC transfers reducing equivalents from the electron donor to the oxygenase component, which in turn transfers electrons to the oxygen molecules. The oxygenase components are oligomers, either (alpha)n or (alpha)n(beta)n. The alpha subunits are the catalytic components and have an N-terminal domain, which binds a Rieske-like 2Fe-2S cluster, and a C-terminal domain which binds the non-heme Fe(II). The Fe(II) is co-ordinated by conserved His and Asp residues. Oxygenases belonging to this family include the alpha subunits of Pseudomonas resinovorans strain CA10 anthranilate 1,2-dioxygenase, Stenotrophomonas maltophilia dicamba O-demethylase, Ralstonia sp. U2 salicylate-5-hydroxylase, Cycloclasticus sp. strain A5 polycyclic aromatic hydrocarbon dioxygenase, toluene 2,3-dioxygenase from Pseudomonas putida F1, dioxin dioxygenase of Sphingomonas sp. Strain RW1, plant choline monooxygenase, and the polycyclic aromatic hydrocarbon (PAH)-degrading ring-hydroxylating dioxygenase from Sphingomonas CHY-1. This group also includes the C-terminal catalytic domains of MupW, part of the mupirocin biosynthetic gene cluster in Pseudomonas fluorescens, and Pseudomonas aeruginosa GbcA (glycine betaine catabolism A). This family belongs to the SRPBCC (START/RHO_alpha_C/PITP/Bet_v1/CoxG/CalC) domain superfamily of proteins that bind hydrophobic ligands. SRPBCC domains have a deep hydrophobic ligand-binding pocket.
Structure:3GOB_A; Stenotrophomonas maltophilia oxygenase component of dicamba monooxygenase binds 3,6-dichlorosalicylic acid (the reaction product, contacts at 4A) and Co(II).
Jiyao W et al.(2023). "The conserved domain database in 2023.",