N-terminal, non-catalytic, domain of BphC5 (2,3-dihydroxybiphenyl 1,2-dioxygenase) from Rhodococcus rhodochrous K37, and similar proteins
2,3-dihydroxybiphenyl 1,2-dioxygenase (BphC) catalyzes the extradiol ring cleavage reaction of 2,3-dihydroxybiphenyl, the third step in the polychlorinated biphenyls (PCBs) degradation pathway (bph pathway). The enzyme contains a N-terminal and a C-terminal domain of similar structure fold, resulting from an ancient gene duplication. BphC belongs to the type I extradiol dioxygenase family, which requires a metal in the active site for its catalytic activity. Polychlorinated biphenyl degrading bacteria demonstrate multiplicity of BphCs. Bacterium Rhodococcus rhodochrous K37 has eight genes encoding BphC enzymes. This family includes the N-terminal domain of BphC5-RrK37. The crystal structure of the protein from Novosphingobium aromaticivorans has a Mn(II)in the active site, although most proteins of type I extradiol dioxygenases are activated by Fe(II).
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