Identification of a phenolic 3-O-methyltransferase in the lignin-degrading fungus Phanerochaete chrysosporium

Jeffers, Maurice R.; McRoberts, W. Colin; Harper, David B.

doi:10.1099/00221287-143-6-1975

Cited by 25 publications

(19 citation statements)

References 16 publications

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“…O-Methyltransferases are also likely required to introduce the two ring methoxyl groups in veratryl alcohol (34), and five genes encoding them were upregulated (Phach ID 2974896, 1961248, 2661209, 2990377, and 3023907), although their specific biosynthetic roles remain to be determined. Veratryl alcohol levels may additionally be maintained in a salvage reaction via reductive recycling of the veratraldehyde produced when LiPs oxidize the alcohol.…”

Section: Resultsmentioning

confidence: 99%

Regulation of Gene Expression during the Onset of Ligninolytic Oxidation by Phanerochaete chrysosporium on Spruce Wood

Korripally

Hunt

Houtman

et al. 2015

Appl Environ Microbiol

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Since uncertainty remains about how white rot fungi oxidize and degrade lignin in wood, it would be useful to monitor changes in fungal gene expression during the onset of ligninolysis on a natural substrate. We grew Phanerochaete chrysosporium on solid spruce wood and included oxidant-sensing beads bearing the fluorometric dye BODIPY 581/591 in the cultures. Confocal fluorescence microscopy of the beads showed that extracellular oxidation commenced 2 to 3 days after inoculation, coincident with cessation of fungal growth. Whole transcriptome shotgun sequencing (RNA-seq) analyses based on the v.2.2 P. chrysosporium genome identified 356 genes whose transcripts accumulated to relatively high levels at 96 h and were at least four times the levels found at 40 h. Transcripts encoding some lignin peroxidases, manganese peroxidases, and auxiliary enzymes thought to support their activity showed marked apparent upregulation. The data were also consistent with the production of ligninolytic extracellular reactive oxygen species by the action of manganese peroxidase-catalyzed lipid peroxidation, cellobiose dehydrogenase-catalyzed Fe 3؉ reduction, and oxidase-catalyzed H 2 O 2 production, but the data do not support a role for iron-chelating glycopeptides. In addition, transcripts encoding a variety of proteins with possible roles in lignin fragment uptake and processing, including 27 likely transporters and 18 cytochrome P450s, became more abundant after the onset of extracellular oxidation. Genes encoding cellulases showed little apparent upregulation and thus may be expressed constitutively. Transcripts corresponding to 165 genes of unknown function accumulated more than 4-fold after oxidation commenced, and some of them may merit investigation as possible contributors to ligninolysis. T he biodegradation of lignocellulose requires the disruption of its lignin, which shields the metabolically assimilable polysaccharides in this recalcitrant natural composite. Although a variety of microorganisms can attack lignocellulose, white rot basidiomycetes are uniquely efficient at this process, cleaving the recalcitrant intermonomer linkages of lignin via extracellular oxidative mechanisms and mineralizing many of the resulting fragments to carbon dioxide (1). Considerable progress has been made in understanding this process in the extensively researched white rot fungus Phanerochaete chrysosporium, which expresses important components of its ligninolytic system in response to nutrient limitation as part of its secondary metabolism. Biochemical and genetic evidence points to an important role in P. chrysosporium for secreted lignin peroxidases (LiPs), manganese peroxidases (MnPs), and H 2 O 2 -producing oxidases, which are thought to work together to cleave lignin into low-molecular-weight fragments (2). However, many aspects of ligninolysis by P. chrysosporium remain poorly understood.First, uncertainty remains about the process of lignin depolymerization. White rot fungi remove lignin not only from the surface of the wood cel...

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Section: Resultsmentioning

confidence: 99%

Regulation of Gene Expression during the Onset of Ligninolytic Oxidation by Phanerochaete chrysosporium on Spruce Wood

Korripally

Hunt

Houtman

et al. 2015

Appl Environ Microbiol

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“…Wood-rotting fungi synthesize methylated aromatic compounds, e.g., veratryl alcohol de novo from glucose, but it was found that the white-rot fungi P. chrysosporium, P. radiata, and Coriolus versicolor use chloromethane (CH 3 Cl) as methyl donor in these reactions (Harper et al, 1990). Two types of O-methyl transferases utilizing S-adenosyl methionine were purified from mycelial extracts of P. chrysosporium, an enzyme methylating phenolic compounds in para (Jeffers, McRoberts, & Harper, 1997) or and another enzyme in meta position (Coulter, Kennedy, McRoberts, & Harper, 1993).…”

Section: O-methylmentioning

confidence: 99%

Aromatic Metabolism of Filamentous Fungi in Relation to the Presence of Aromatic Compounds in Plant Biomass

Mäkelä

Marinovíc

Nousiainen

et al. 2015

Advances in Applied Microbiology

106

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“…It should be noted that the specific activity of purified CPOMT is very low when it is compared with the specific activities of other SAM-dependent fungal phenol methyltransferases reported previously (9,15). This fact could be explained if halogenated phenols are not the true physiological substrates of the enzyme.…”

Section: Discussionmentioning

confidence: 75%

Characterization of an Inducible Chlorophenol O -Methyltransferase from Trichoderma longibrachiatum Involved in the Formation of Chloroanisoles and Determination of Its Role in Cork Taint of Wines

Coque

Álvarez-Rodríguez

Larriba

2003

Appl Environ Microbiol

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A novel S-adenosyl-L-methionine (SAM)-dependent methyltransferase catalyzing the O methylation of several chlorophenols and other halogenated phenols was purified 220-fold to apparent homogeneity from mycelia of Trichoderma longibrachiatum CECT 20431. The enzyme could be identified in partially purified protein preparations by direct photolabeling with [methyl-3 H]SAM, and this reaction was prevented by previous incubation with S-adenosylhomocysteine. Gel filtration indicated that the M r was 112,000, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme was composed of two subunits with molecular weights of approximately 52,500. The enzyme had a pH optimum between 8.2 and 8.5 and an optimum temperature of 28°C, with a pI of 4.9. The K m values for 2,4,6-trichlorophenol and SAM were 135.9 ؎ 12.8 and 284.1 ؎ 35.1 M, respectively. S-Adenosylhomocysteine acted as a competitive inhibitor, with a K i of 378.9 ؎ 45.4 M. The methyltransferase was also strongly inhibited by low concentrations of several metal ions, such as Cu 2؉ , Hg 2؉ , Zn 2؉ , and Ag ؉ , and to a lesser extent by p-chloromercuribenzoic acid, but it was not significantly affected by several thiols or other thiol reagents. The methyltransferase was specifically induced by several chlorophenols, especially if they contained three or more chlorine atoms in their structures. Substrate specificity studies showed that the activity was also specific for halogenated phenols containing fluoro, chloro, or bromo substituents, whereas other hydroxylated compounds, such as hydroxylated benzoic acids, hydroxybenzaldehydes, phenol, 2-metoxyphenol, and dihydroxybenzene, were not methylated.

show abstract

Identification of a phenolic 3-O-methyltransferase in the lignin-degrading fungus Phanerochaete chrysosporium

Cited by 25 publications

References 16 publications

Regulation of Gene Expression during the Onset of Ligninolytic Oxidation by Phanerochaete chrysosporium on Spruce Wood

Regulation of Gene Expression during the Onset of Ligninolytic Oxidation by Phanerochaete chrysosporium on Spruce Wood

Aromatic Metabolism of Filamentous Fungi in Relation to the Presence of Aromatic Compounds in Plant Biomass

Characterization of an Inducible Chlorophenol O -Methyltransferase from Trichoderma longibrachiatum Involved in the Formation of Chloroanisoles and Determination of Its Role in Cork Taint of Wines

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