Rieske non-heme iron oxygenase (RO) family, Vanillate-O-demethylase oxygenase (VanA) and dicamba O-demethylase oxygenase (DdmC) subfamily, N-terminal Rieske domain of the oxygenase alpha subunit; ROs comprise a large class of aromatic ring-hydroxylating dioxygenases that enable microorganisms to tolerate and utilize aromatic compounds for growth. The oxygenase alpha subunit contains an N-terminal Rieske domain with an [2Fe-2S] cluster and a C-terminal catalytic domain with a mononuclear Fe(II) binding site. The Rieske [2Fe-2S] cluster accepts electrons from a reductase or ferredoxin component and transfers them to the mononuclear iron for catalysis. Vanillate-O-demethylase is a heterodimeric enzyme consisting of a terminal oxygenase (VanA) and reductase (VanB) components. This enzyme reductively catalyzes the conversion of vanillate into protocatechuate and formaldehyde. Protocatechuate and vanillate are important intermediate metabolites in the degradation pathway of lignin-derived compounds such as ferulic acid and vanillin by soil microbes. DDmC is the oxygenase component of a three-component dicamba O-demethylase found in Pseudomonas maltophila, that catalyzes the conversion of a widely used herbicide called herbicide dicamba (2-methoxy-3,6-dichlorobenzoic acid) to DCSA (3,6-dichlorosalicylic acid).
Jiyao W et al.(2023). "The conserved domain database in 2023.",