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

Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 02/2013; 79(8). DOI: 10.1128/AEM.03767-12
Source: PubMed


Cytochrome P450 monooxygenases (P450s) are known to oxidize hydrocarbons albeit with limited substrate specificity across classes of these compounds. Here we report a P450 monooxygenase (CYP63A2) from the model ligninolytic white rot fungus Phanerochaete chrysosporium that was found to possess a broad oxidizing capability toward structurally diverse hydrocarbons belonging to mutagenic/carcinogenic fused-ring higher molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs), endocrine-disrupting long-chain alkylphenols (APs), and crude oil aliphatic hydrocarbons n-alkanes. A homology-based 3D-model revealed presence of an extraordinarily large active site cavity in CYP63A2 compared to the mammalian PAH-oxidizing (CYP3A4, CYP1A2 and CYP1B1) and bacterial aliphatic hydrocarbon-oxidizing (CYP101D and CYP102A1) P450s. This structural feature in conjunction with ligand docking simulations suggested potential versatility of the enzyme. Experimental characterization using recombinantly expressed CYP63A2 revealed its ability to oxidize HMW-PAHs of varying ring size, including 4 rings (pyrene and fluoranthene), 5 rings [lsqb]benzo(a)pyrene[rsqb], and 6 rings [lsqb]benzo(ghi)perylene[rsqb]; the highest enzymatic activity being toward the 5-ring PAH followed by the 4-ring and 6-ring PAHs, in that order. CYP63A2 activity yielded monohydroxylated PAH metabolites. The enzyme was found to also act as an alkane ω-hydroxylase that oxidized varying chain-length n-alkanes (C9-C12 and C15-C19) as well as alkyl side-chains (C3-C9) in alkylphenols (APs). CYP63A2 showed preferential oxidation of long chain-length APs and alkanes. To our knowledge, this is the first of its kind P450 across biological kingdoms that possesses such broad substrate specificity toward structurally diverse xenobiotics (PAHs, APs, and alkanes), making it a potent enzyme biocatalyst candidate to handle mixed pollution (e.g., crude oil spills).

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Available from: Khajamohiddin Syed, Dec 04, 2014
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    • "Direct experimental evidence is necessary to validate this idea. Cytochrome P450 monooxygenases are alternative biocatalysts for the oxidation of aliphatic and aromatic hydrocarbons in many hydrocarbon-degrading microorganisms (van Beilen et al. 2006; Syed et al. 2013). Altogether, 16 cyp genes were found in R. erythropolis PR4. "
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    Applied Microbiology and Biotechnology 09/2015; DOI:10.1007/s00253-015-6936-z · 3.34 Impact Factor
    • "14.14.1) NAD(P)H/O 2 PAHs, aliphatic hydrocarbons, pesticides Kawahigashi et al. 2007; Syed et al. 2013 Tyrosinase (EC −/O 2 Phenolic compounds (including halogenated phenols) dyes, phthalates derivatives Battaini et al. 2002; Marino et al. 2011; Franciscon et al. 2012; da Silva et al. 2013 "
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    Applied Microbiology and Biotechnology 08/2015; DOI:10.1007/s00253-015-6872-y · 3.34 Impact Factor
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    • "Recent studies on fungal organisms revealed the presence of a large number of P450 contingents in their genomes, with some exceptions [4], [24], [39]. Subsequent functional studies suggested that fungal P450s are catalytically diverse [19], [36], [56] and perform extraordinary oxidation activity compared to P450s across the biological kingdoms [21]. The latest study conducted in our laboratory revealed the presence of a large number of thermostable P450s with biotechnological potential in fungi [33]. "
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    PLoS ONE 04/2014; 9(4):e95616. DOI:10.1371/journal.pone.0095616 · 3.23 Impact Factor
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