P450 monooxygenases (P450ome) of the model white rot fungusPhanerochaete chrysosporium

Abstract

Phanerochaete chrysosporium, the model white rot fungus, has been the focus of research for the past about four decades for understanding the mechanisms and processes of biodegradation of the natural aromatic polymer lignin and a broad range of environmental toxic chemicals. The ability to degrade this vast array of xenobiotic compounds was originally attributed to its lignin-degrading enzyme system (LDS), mainly the extracellular peroxidases. However, subsequent physiological, biochemical, and/or genetic studies by us and others identified the involvement of a peroxidase-independent oxidoreductase system, the cytochrome P450 monooxygenase system. The whole genome sequence revealed an extraordinarily large P450 contingent (P450ome) with an estimated 149 P450s in this organism. This review focuses on the current status of understanding on the P450 monooxygenase system of P. chrysosporium in terms of pre-genomic and post-genomic identification, structural and evolutionary analysis, transcriptional regulation, redox partners, and functional characterization for its biodegradative potential. Future research on this catalytically diverse oxidoreductase enzyme system and its major role as a newly emerged player in xenobiotic metabolism/degradation is discussed.

Transcriptomic Responses of Phanerochaete chrysosporium to Oak Acetonic Extracts: Focus on a New Glutathione Transferase

“…The apparent K cat value for HNE was determined in the presence of 2 mM GSH using an HNE range from 0 to 0.5 mM. Glutathione peroxidase activities were monitored as described previously (14) 8.0, was incubated in the presence of GSH, 200 M NADPH, and 0.5 IU glutathione reductase (GR). The activity was analyzed by monitoring the decrease in absorbance arising from NADPH oxidation in this coupled enzyme assay system showing the formation of oxidized glutathione (GSSG).…”

“…Thus, fungi have developed an efficient detoxification system. It is composed of enzymes encoded by multigenic families, which are expanded in these genomes and exhibit versatile activities, allowing them to accept a broad range of compounds such as substrates (8,9). This system is composed mainly of oxidases as cytochrome P450 monooxygenases (CytP450), conjugating enzymes, and transporters.…”

CYP63A2, a Catalytically Versatile Fungal P450 Monooxygenase Capable of Oxidizing Higher-Molecular-Weight Polycyclic Aromatic Hydrocarbons, Alkylphenols, and Alkanes

“…Phanerochaete chrysosporium has been the most intensively studied model white rot basidiomycete for understanding the mechanisms of degradation of lignin, the most abundant aromatic polymer on earth (13), and various xenobiotic structures, including PAHs and APs (14). Pregenomic studies from our laboratory led to the first isolation of complete P450 genes, namely, CYP63A1 and CYP63A2 (15) in P. chrysosporium.…”

“…These genes, though tandemly linked, were found to be inducible to different extents, by a wide range of xenobiotic structures, including aliphatic, aromatic/ polyaromatic, and alkyl-substituted aromatic compounds (16). Subsequent whole-genome sequencing of P. chrysosporium (17) revealed the presence of an extraordinarily large contingent of P450 genes (149 complete P450 genes and 12 pseudogenes) in this organism (14,17). Although xenobiotic induction data on several individual P450s implied their functional potential, experimental analysis to understand their specific role in catalysis was hampered due to the difficulty in active heterologous expression of these enzymes (18,19).…”

Cytochrome P450 monooxygenase analysis in free-living and symbiotic microalgae Coccomyxa sp. C-169 and Chlorella sp. NC64A

“…Oxidation of a wide variety of substrates in stereo-and regio-specific manner credited these enzymes' use in the generation of drugs (Ingelman-Sundberg 2004, Guengerich 2006, fine chemicals and cosmetics (Guengerich 2002) and biofuels ) and as biosensors (Paternolli et al 2004) and bioremediation agents (Guengerich 1995, Urlacher andEiben 2006). A summary of P450s' potential biotechnological applications has been discussed elsewhere (Syed and Yadav 2012).…”