title: Characterisation of two novel CYP4 genes from the marine polychaete Nereis virens and their involvement in pyrene hydroxylase activity.
abstract: Cytochrome P450 enzymes (CYP enzymes) catalyse the initial step in biotransformation of xenobiotics like polycyclic aromatic hydrocarbons (PAHs). The marine polychaete Nereis virens has a high capacity for biotransformation of PAHs. In the present study, the complete cDNA sequences of two novel CYP genes isolated from N. virens gut tissue are reported. One named CYP342A1, the first member of a new family and the other named CYP4BB1, the first member of a new subfamily. This is the first investigation of specific CYP enzymes from marine polychaetes in which catalytic activity has been determined. Both CYP enzymes had monooxygenase activity and catalysed hydroxylation of pyrene to 1-hydroxypyrene. Based on the present results it is likely that both CYP4BB1 and CYP342A1 are involved in xenobiotic biotransformation. Furthermore, site-directed mutagenesis of the conserved cysteine residue of the heme binding domain resulted in complete loss of monooxygenase activity of both CYP enzymes, indicating that this cysteine residue is indispensable for monooxygenase activity of invertebrate CYP enzymes, as has been well documented in vertebrates. Considering the important role of CYP enzymes in biotransformation of xenobiotics and the presence of N. virens in estuarine environments that accumulates organic xenobiotics, our results are important in understanding the molecular mechanism of biotransformation in marine polychaetes.
authors.affiliation: Department of Life Sciences and Chemistry, Roskilde University, Denmark. annejoer@ruc.dk
authors.forename: Anne
authors.initials: A
authors.lastname: Jørgensen
authors.forename: Lene Juel
authors.initials: LJ
authors.lastname: Rasmussen
authors.forename: Ole
authors.initials: O
authors.lastname: Andersen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D011077:Polychaeta / Q000201:enzymology* / Q000235:genetics; D011721:Pyrenes / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D011721:Pyrenes; D003577:Cytochrome P-450 Enzyme System; C033146:1-hydroxypyrene