title: Two identical nonylphenol monooxygenase genes linked to IS6100 and some putative insertion sequence elements in Sphingomonas sp. NP5.
abstract: Sphingomonas sp. NP5 can degrade a wide range of nonylphenol (NP) isomers that have widely contaminated aquatic environments as major endocrine-disrupting chemicals. To understand the biochemical and genetic backgrounds of NP degradation, a gene library of strain NP5 was constructed using a broad-host-range vector pBBR1MCS-2 and introduced into Sphingobium japonicum UT26. Several transformants accumulated reddish brown metabolites on agar plates dispersed with a mixture of NP isomers. Two different DNA fragments (7.6 and 9.3 kb) involved in the phenotype were isolated from the transformants. Sequence analysis revealed that both fragments contained an identical 1593 bp monooxygenase gene (nmoA), the predicted protein sequence of which showed 83 % identity to the octylphenol-4-monooxygenase of Sphingomonas sp. PWE1. The nmoA gene in the 7.6 kb fragment was surrounded by an IS21-type insertion sequence (IS) and IS6100, while another in the 9.3 kb fragment was adjacent to an IS66-type IS, suggesting that they have been acquired through multiple transposition events. A fast-growing recombinant Pseudomonas putida strain harbouring nmoA was constructed and used for degradation of a chemically synthesized NP isomer, 4-(1-ethyl-1-methylhexyl)phenol. This strain converted the isomer into hydroquinone stoichiometrically. 3-Methyl-3-octanol, probably originating from the alkyl side chain, was also detected as the metabolite. These results indicate that these two nmoA genes are involved in the NP degradation ability of strain NP5.
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Takeo
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Maeda
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Nishiyama
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Chitoshi
authors.initials: C
authors.lastname: Kitamura
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Dai-Ichiro
authors.initials: DI
authors.lastname: Kato
authors.affiliation: Department of Materials Science and Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Negoro
mesh_terms: D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D015723:Gene Library; D006873:Hydroquinones; D060847:Metabolic Engineering; D006899:Mixed Function Oxygenases / Q000235:genetics*; D008969:Molecular Sequence Data; D010636:Phenols / Q000378:metabolism*; D016958:Pseudomonas putida / Q000235:genetics / Q000254:growth & development; D017422:Sequence Analysis, DNA; D020578:Sphingomonas / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
chemical_list: D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D006873:Hydroquinones; D010636:Phenols; C025256:nonylphenol; D006899:Mixed Function Oxygenases; C031927:hydroquinone