A ubiquitin-like peptide from the mushroom Pleurotus sajor-caju exhibits relatively potent translation-inhibitory and ribonuclease activities.
The fruiting bodies of the edible mushroom Pleurotus sajor-caju were extracted with an aqueous buffer and then subjected to affinity chromatography on Affi-gel Blue gel, ion exchange chromatography on DEAE-cellulose and gel filtration on Superdex 75. From the fraction of the extract adsorbed on Affi-gel Blue gel and unadsorbed on DEAE-cellulose, a 9.5 kDa peptide with an N-terminal sequence similar to ubiquitin was isolated with a yield of 0.25 mg/kg mushroom. The peptide inhibited cell-free translation with an IC(50) of 30 nM. It exhibited a ribonuclease activity of 450 U/mg toward yeast transfer RNA. The activities were substantially more potent than those of previously isolated mushroom ubiquitin-like protein and peptide.
Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, PR China. biochemistry@cuhk.edu.hk
T B
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Ng
S K
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Lam
S Y
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Chan
D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D020076:Pleurotus / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000502:physiology*; D012260:Ribonucleases / Q000378:metabolism*; D025801:Ubiquitin / Q000235:genetics
D005656:Fungal Proteins; D010455:Peptides; D025801:Ubiquitin; D012260:Ribonucleases