title: Enhanced degradation of polychlorinated biphenyls by directed evolution of biphenyl dioxygenase.
abstract: Biphenyl dioxygenases (BP Dox) from different organisms, which are involved in the initial oxygenation and subsequent degradation of polychlorinated biphenyls (PCB), are similar in structure but have different functions. The large subunit of BP Dox, encoded by the bphA1 gene, is crucial for substrate selectivity. Using the process of DNA shuffling, we randomly recombined the bphA1 genes of Pseudomonas pseudoalcaligenes KF707 and Burkholderia cepacia LB400 and selected for genes that expressed proteins with altered function. Upon expression in Escherichia coli, some of these evolved genes exhibited enhanced degradation capacity, not only for PCB and related biphenyl compounds, but for single aromatic hydrocarbons such as benzene and toluene, which are poor substrates for the original BP Dox.
authors.affiliation: Department of Agricultural Chemistry, Kyushu University, Fukuoka, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kumamaru
authors.forename: H
authors.initials: H
authors.lastname: Suenaga
authors.forename: M
authors.initials: M
authors.lastname: Mitsuoka
authors.forename: T
authors.initials: T
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Furukawa
mesh_terms: D000595:Amino Acid Sequence; D001673:Biodegradation, Environmental; D016956:Burkholderia cepacia / Q000235:genetics*; D002678:Chimera; D004926:Escherichia coli / Q000235:genetics*; D007506:Iron-Sulfur Proteins; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011549:Pseudomonas / Q000235:genetics*; D013379:Substrate Specificity
chemical_list: D007506:Iron-Sulfur Proteins; D011078:Polychlorinated Biphenyls; D010105:Oxygenases; C074161:biphenyl-2,3-dioxygenase