title: Metabolism of mono- and dichloro-dibenzo-p-dioxins by Phanerochaete chrysosporium cytochromes P450.
abstract: The white-rot fungus Phanerochaete chrysosporium possesses biodegradative capabilities of polychlorinated dibenzo-p-dioxins (PCDDs). One hundred twenty yeast clones expressing individual P450s of P. chrysosporum (PcCYPs), generated in our previous efforts, were screened for transformation of dioxin, and 40 positive clones were obtained. Of these clones, six clones showed metabolism of 2-chloro-dibenzo-p-dioxin, and a microsomal PcCYP designated as PcCYP11a3 showed much higher activity than any other PcCYPs. The turnover numbers of hydroxylation activities of PcCYP11a3 toward 1-MCDD (58 min(-1)) and 2-MCDD (13 min(-1)) are more than 200 times higher than those of previously reported PcCYP65a2. In addition, PcCYP11a3 catalyzes hydroxylation of 2,3-dichlorodibenzo-p-dioxin. To our best knowledge, PcCYP11a3 has the highest activity toward PCDDs among the known CYPs derived from microorganisms. Although PcCYP11a3 showed no detectable activity toward 2,7-dichloro-dibenzop-dioxin and 2,3,7-trichloro-dibenzo-p-dioxin, PcCYP11a3 is promising as a template whose activity would be enhanced by site-directed mutagenesis.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Toyama Prefectural University, Toyama, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kasai
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ikushiro
authors.forename: Raku
authors.initials: R
authors.lastname: Shinkyo
authors.forename: Kaori
authors.initials: K
authors.lastname: Yasuda
authors.forename: Shinji
authors.initials: S
authors.lastname: Hirosue
authors.forename: Akira
authors.initials: A
authors.lastname: Arisawa
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ichinose
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Wariishi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Sakaki
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004147:Dioxins / Q000378:metabolism*; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D020075:Phanerochaete / Q000378:metabolism*
chemical_list: D004147:Dioxins; D006843:Hydrocarbons, Chlorinated; D003577:Cytochrome P-450 Enzyme System; C020887:dibenzo(1,4)dioxin