This CD includes the putative hydrocarbon oxygenase, MocD, a bacterial rhizopine (3-O-methyl-scyllo-inosamine, 3-O-MSI) oxygenase, and other related proteins. It has been proposed that MocD, MocE (Rieske-like ferredoxin), and MocF (ferredoxin reductase) under the regulation of MocR, act in concert to form a ferredoxin oxygenase system that demethylates 3-O-MSI to form scyllo-inosamine. This domain family appears to be structurally related to the membrane fatty acid desaturases and the alkane hydroxylases. They all share in common extensive hydrophobic regions that would be capable of spanning the membrane bilayer at least twice. Comparison of sequences also reveals the existence of three regions of conserved histidine cluster motifs that contain eight histidine residues: HXXXH, HXXHH, and HXXHH. These histidine residues are reported to be catalytically essential and proposed to be the ligands for the iron atoms contained within homologs, stearoyl CoA desaturase and alkane hydroxylase.
Jiyao W et al.(2023). "The conserved domain database in 2023.",