Molecular characterization of the enzymes involved in the degradation of a brominated aromatic herbicide

摘要: Dehalogenation is the key step in degradation of halogenated aromatics, while reductive dehalogenation originally thought to rarely occur aerobes. In this study, an aerobic strain Comamonas sp. 7D-2 was shown degrade brominated aromatic herbicide bromoxynil completely and release two equivalents bromides under conditions. The enzymes involved 4-carboxy-2-hydroxymuconate-6-semialdehyde, including nitrilase, dehalogenase (BhbA), 4-hydroxybenzoate 3-monooxygenase protocatechuate 4,5-dioxygenase, were molecularly characterized. novel BhbA be a complex respiration-linked (RdhA) domain NAD(P)H-dependent oxidoreductase have features anaerobic respiratory RdhAs, predicted binding motifs for [4Fe-4S] clusters close association with hydrophobic membrane protein (BhbB). BhbB confirmed anchor membrane. partially purified found use NAD(P)H as electron donors. Full-length bhbA homologues almost exclusively marine proteobacteria, suggesting that occurs extensively aerobes horizontally transferred from microorganisms. discovery functional ring-cleavage oxygenases aerobe opens up possibilities basic research well potential application bioremediation.