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Characterization of glycopeptide from white-, brown- and soft rot fungi
2002 - IRG/WP 02-10424
Extracellular low-molecular-weight substances that catalyze a redox reaction between O2 and electron donors to produce hydroxyl radicals have been isolated from wood degrading cultures of white-rot, brown-rot, and soft-rot fungi. They contained protein, neutral carbohydrate, and Fe(II). These substances were glycosylated (glycated) peptides and suggested to form Amadori product (ketoamine). The glycopeptides are involved in all three types of decay.
H Tanaka, S Itakura, A Enoki

Extracellular substance from the white rot basidiomycete Irpex lacteus involved in wood degradation
1992 - IRG/WP 92-1571
Cellulases, phenol oxidase, and a substance that both produced and reduced H2O2 were isolated from cultures containing wood or glucose on which the white-rot fungus Irpex lacteus was growing. The rate of wood degradation by the fungus with different amounts of glucose in the medium was measured. More of the substance that produced and reduced H2O2 was found extracellularly in cultures containing wood than in cultures containing glucose. The extent of one-electron oxidation activity of the extracellular substance was correlated with that of the wood-degrading activity, but the extent of phenol oxidase activity was not. The extracellular substance catalyzed the hydroxylation of phenol to hydroquinone and catechol in the presence of H2O2 or of NADH and O2. The substance seemed to be a glycopeptide containing Fe(II) and its molecular weight was very low.
H Tanaka, T Hirano, G Fuse, A Enoki

Isolation and characterization of hydroxyl-radical-producing glycopeptide genes from the white-rot basidiomycete Phanerochaete chrysosporium
2006 - IRG/WP 06-10588
During wood decay, the white-rot basidiomycete Phanerochaete chrysosporium secretes low-molecular-weight glycopeptides that catalyze a redox reaction between O2 and electron donors to produce hydroxyl radical. This reaction accounts for most of the hydroxyl radical produced in wood-degrading cultures of P. chrysosporium. In combination with phenol oxidases, hydroxyl radical is believed to play a role in lignin degradation. Low-molecular-weight fractions with high one-electron oxidation activity were isolated from wood-containing cultures of P. chrysosporium. They were composed of protein (55% w/w), neutral carbohydrate (25% w/w), and Fe(II) (0.04% w/w). A partially-purified glycopeptide was separated by tricine-SDS-PAGE and the bands were excised and digested with endoproteinase Asp-N. The N-terminal and four internal fragments were sequenced. BLAST and FASTA searches revealed no homologies between these amino-acid sequences and known proteins. However 70-100% similarities were found when the P. chrysosporium genome database was searched for the amino-acid sequences. cDNAs and two putative genes encoding these glycopeptides, glp1 and glp2, were isolated and sequenced. The 875-bp glp1 and 864-bp glp2 are located on scaffold 2 of the P. chrysosporium genome. These presumptive genes each consist of seven introns and eight exons. The latter encode a predicted mature peptide of 138 amino acids and a 22-amino-acid signal sequence for secretion. The predicted peptide sequences are nearly identical to N-terminal and internal sequences obtained from the partially-purified glycopeptide. The molecular weights of the deduced mature proteins coincide with the molecular weight of the glycopeptide as determined by tricine-SDS-PAGE. Finally, the amino-acid composition of the glycopeptide is nearly identical to the amino-acid compositions deduced from the glp1 and glp2 sequences. It appears that glp1 and glp2 encode the partially-purified hydroxyl-radical-producing glycopeptide Glp.
H Tanaka, G Yoshida, Y Baba, K Matsumura, S Itakura, A Enoki