C-terminal domain of 2,3-dihydroxybiphenyl 1,2-dioxygenase
This subfamily contains the C-terminal, catalytic, domain of BphC1-RGP6 and similar proteins. BphC catalyzes the extradiol ring cleavage reaction of 2,3-dihydroxybiphenyl, the third step in the polychlorinated biphenyls (PCBs) degradation pathway (bph pathway). This subfamily of BphCs belongs to the type I extradiol dioxygenase family, which require a metal in the active site in its catalytic mechanism. Polychlorinated biphenyl degrading bacteria demonstrate a multiplicity of BphCs. For example, three types of BphC enzymes have been found in Rhodococcus globerulus (BphC1-RGP6 - BphC3-RGP6), all three enzymes are type I extradiol dioxygenases. BphC1-RGP6 has an internal duplication, it is a two-domain dioxygenase which forms octamers, and has Fe(II) at the catalytic site. Its C-terminal repeat is represented in this subfamily. BphC2-RGP6 and BphC3-RGP6 are one-domain dioxygenases, they belong to a different subfamily of the ED_TypeI_classII_C (C-terminal domain of type I, class II extradiol dioxygenases) family.