title: Crystal structure of the biphenyl-cleaving extradiol dioxygenase from a PCB-degrading pseudomonad.
abstract: Polychlorinated biphenyls (PCBs) typify a class of stable aromatic pollutants that are targeted by bioremediation strategies. In the aerobic degradation of biphenyl by bacteria, the key step of ring cleavage is catalyzed by an Fe(II)-dependent extradiol dioxygenase. The crystal structure of 2,3-dihydroxybiphenyl 1,2-dioxygenase from a PCB-degrading strain of Pseudomonas cepacia has been determined at 1.9 angstrom resolution. The monomer comprises amino- and carboxyl-terminal domains. Structural homology between and within the domains reveals evolutionary relationships within the extradiol dioxygenase family. The iron atom has five ligands in square pyramidal geometry: one glutamate and two histidine side chains, and two water molecules.
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D001673:Biodegradation, Environmental; D018360:Crystallography, X-Ray; D049308:Dioxygenases; D019143:Evolution, Molecular; D005296:Ferrous Compounds / Q000737:chemistry / Q000378:metabolism; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D010105:Oxygenases / Q000737:chemistry* / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011549:Pseudomonas / Q000201:enzymology*; D016415:Sequence Alignment
chemical_list: D005296:Ferrous Compounds; D008024:Ligands; D011078:Polychlorinated Biphenyls; D010105:Oxygenases; D049308:Dioxygenases; C074272:2,3-dihydroxybiphenyl oxygenase; D010100:Oxygen