Identification of cytochrome P450 monooxygenase genes from the white-rot fungus Phlebia brevispora

Cytochrome P450 enzymes (CYPs) constitute a large superfamily of heme-containing monooxygenases that are widely distributed in all kingdoms of life (Nelson 2009). CYPs are involved in the metabolism of a wide variety of endogenous and xenobiotic compounds by catalyzing regio- and stereospecific monooxygenation with an oxygen atom generated from molecular oxygen. Mammalian CYPs have been studied extensively because of their leading role in drug and xenobiotic metabolism and detoxification (Allis et al. 2002; Inouye et al. 2002; McGraw JE and Waller 2006; Shimada 2006; Vrba et al. 2004; Warner et al. 2009; Yamazaki 2000; Zhang et al. 2006). CYPs from bacteria, yeast and fungi have also been well studied in the biosynthesis of essential compounds like ergosterol, which is a constituent of fungal cell membranes, and in the detoxification and biodegradation of a broad spectrum of environmental chemical pollutants (Kelly et al. 1997; Kelly et al. 2003; Lamb et al. 2000; Seth-Smith et al. 2008; van den Brink et al. 1998).The wood-rotting Basidiomycetes, white-rot fungi, have been extensively used for biodegradation of various chemical pollutants. The ability to degrade such structurally diverse chemical pollutants has generally been attributed to a lignin-degrading enzyme system, including mainly lignin peroxidase, manganese-dependent peroxidase and laccase produced by these fungi (Cameron et al. 2000; Fujihiro et al. 2009; Han et al. 2004; Mayer and Staples 2002; Takagi et al. 2007; Van Aken et al. 1999). However, several studies pointed out that white-rot fungi are capable of degrading certain xenobiotics under culturing conditions that did not induce the production of lignin peroxidase, manganese-dependent peroxidase or laccase (Bumpus and Brock 1988; Mileski et al. 1988; Yadav and Reddy 1993; Yadav et al. 1995). Therefore, besides such lignin-degrading enzymes, alternative oxygenases, CYPs, are apparently involved in catalyzing degradation of several xenobiotics. In pa