Cytochrome P450 monooxygenases (P450s) involved in anthracene metabolism by the white-rot basidiomycete Phanerochaete chrysosporium were identified by comprehensive screening of both catalytic potentials and transcriptomic profiling. Functional screening of P. chrysosporium P450s (PcCYPs) revealed that 14 PcCYP species catalyze stepwise conversion of anthracene to anthraquinone via intermediate formation of anthrone. Moreover, transcriptomic profiling explored using a complementary DNA microarray system demonstrated that 12 PcCYPs are up-regulated in response to exogenous addition of anthracene. Among the up-regulated PcCYPs, five species showed catalytic activity against anthracene. Based upon both catalytic and transcriptional properties, these five species are most likely to play major roles in anthracene metabolic processes in vivo. Thus, the combination of functional screening and a microarray system may provide a novel strategy for obtaining a thorough understanding of the catalytic functions and biological impacts of PcCYPs.
"Hence, most conclusions were drawn from the results of indirect experiments consisting in the addition of specific cytochrome P450 inhibitors to the culture medium, such as piperonyl butoxide and 1-aminobenzotriazole, the same strategy used in the present work. Two recent studies reinforced the importance of this system in the P. chrysosporium degradation of pentachlorophenol  and phenanthrene . In the latter study strong evidence has been presented for the participation of cytochrome P450 monooxygenases in anthracene metabolism by P. chrysosporium. "
[Show abstract][Hide abstract] ABSTRACT: The white-rot fungus Phanerochaete chrysosporium was investigated for its capacity to degrade the herbicide diuron in liquid stationary cultures. The presence of diuron increased the production of lignin peroxidase in relation to control cultures but only barely affected the production of manganese peroxidase. The herbicide at the concentration of 7 μ g/mL did not cause any reduction in the biomass production and it was almost completely removed after 10 days. Concomitantly with the removal of diuron, two metabolites, DCPMU [1-(3,4-dichlorophenyl)-3-methylurea] and DCPU [(3,4-dichlorophenyl)urea], were detected in the culture medium at the concentrations of 0.74 μ g/mL and 0.06 μ g/mL, respectively. Crude extracellular ligninolytic enzymes were not efficient in the in vitro degradation of diuron. In addition, 1-aminobenzotriazole (ABT), a cytochrome P450 inhibitor, significantly inhibited both diuron degradation and metabolites production. Significant reduction in the toxicity evaluated by the Lactuca sativa L. bioassay was observed in the cultures after 10 days of cultivation. In conclusion, P. chrysosporium can efficiently metabolize diuron without the accumulation of toxic products.
"It is assumed that the high number of CytP450 isoforms found in wood decaying fungi could reflect the ability of these fungi to metabolize and mineralize aromatic compounds resulting from wood extracellular oxidation. The functional diversity of CytP450s has been investigated in particular in P. chrysosporium, where 154 CytP450-encoding genes have been identified in this white-rot basidiomycete (Martinez et al., 2004; Doddapaneni and Yadav, 2005; Chigu et al., 2010; Hirosue et al., 2011). Fourteen PcCytP450s isoforms are able to oxidize anthracene to anthroquinone and numerous isoforms are versatile enzymes accepting a broad range of substrates with varying three-dimensional structures (Hirosue et al., 2011). "
[Show abstract][Hide abstract] ABSTRACT: Fungal degradation of wood is mainly restricted to basidiomycetes, these organisms having developed complex oxidative and hydrolytic enzymatic systems. Besides these systems, wood-decaying fungi possess intracellular networks allowing them to deal with the myriad of potential toxic compounds resulting at least in part from wood degradation but also more generally from recalcitrant organic matter degradation. The members of the detoxification pathways constitute the xenome. Generally, they belong to multigenic families such as the cytochrome P450 monooxygenases and the glutathione transferases. Taking advantage of the recent release of numerous genomes of basidiomycetes, we show here that these multigenic families are extended and functionally related in wood-decaying fungi. Furthermore, we postulate that these rapidly evolving multigenic families could reflect the adaptation of these fungi to the diversity of their substrate and provide keys to understand their ecology. This is of particular importance for white biotechnology, this xenome being a putative target for improving degradation properties of these fungi in biomass valorization purposes.
"Therefore, besides such lignin-degrading enzymes, alternative oxygenases, CYPs, are apparently involved in catalyzing degradation of several xenobiotics. In particular, several specific CYPs from Phanerochaete chrysosporium, the model white-rot fungus, have been studied in the metabolism of xenobiotics (Chigu et al. 2010; Kasai et al. 2010; Matsuzaki and Wariishi 2005; Ning et al. 2010; Subramanian and Yadav 2009; Syed et al. 2010). Since whole genome sequencing of P. chrysosporium has been completed, the molecular diversity of CYPs and the presence of at least 150 CYP genes have been elucidated (Nelson 2009). "
[Show abstract][Hide abstract] ABSTRACT: Three cytochrome P450 monooxygenase (CYP) genes, designated pb-1, pb-2 and pb-3, were isolated from the white-rot fungus, Phlebia brevispora, using reverse transcription PCR with degenerate primers constructed based on the consensus amino acid sequence of eukaryotic CYPs in the O2-binding, meander and heme-binding regions. Individual full-length CYP cDNAs were cloned and sequenced, and the relative nucleotide sequence similarity of pb-1 (1788 bp), pb-2 (1881 bp) and pb-3 (1791 bp) was more than 58%. Alignment of the deduced amino acid (aa) sequences of pb-1-pb-3 showed that these three CYPs belong to the same family with > 40% aa sequence similarity, and pb-1 and pb-3 are in the same subfamily, with > 55% aa sequence similarity. Furthermore, pb-1-pb-3 appeared to be a subfamily of CYP63A (CYP63A1-CYP63A4), found in Phanerochaete chrysosporium. The phylogenetic tree constructed by 500 bootstrap replications using the neighbor-joining method showed that the evolutionary distance between pb-1 and pb-3 was shorter than that between pb-2 and pb-1 (or pb-3). Exon-intron analysis of pb-1 and pb-3 showed that both genes have nearly the same number, size and order of exons and the types of introns, also indicating both genes appear to be evolutionarily close. It is interesting that the transcription level of pb-3 was evidently increased above the pb-1 transcription level by exposure to 12 coplanar PCB congeners and 2,3,7,8-tetrachlorodibenzo-p-dioxin, though the two genes were evolutionarily close.
AMB Express 01/2012; 2(1):8. DOI:10.1186/2191-0855-2-8
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