A novel and potent ribonuclease from fruiting bodies of the mushroom Pleurotus pulmonarius.
A ribonuclease (RNase), with an N-terminal sequence different from those of ribonucleases from the mushrooms Irpex lacteus, Lentinus edodes, Pleurotus ostreatus, Pleurotus tuber-regium, and Volvariella volvacea, was purified from fruiting bodies of the edible mushroom Pleurotus pulmonarius. The N-terminal sequence of P. pulmonarius RNase manifested homology to a portion of the sequences of ribosome inactivating protein abrin-b, abrin-c, and abrin-d, and Bacillus subtilis transcriptional regulator. The ribonuclease was adsorbed on Affi-gel blue gel, CM-Sepharose, and Mono S. It displayed a molecular mass of 14.4 kDa in both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration on Superdex 75. The ribonuclease exhibited an activity of 25 114 U/mg on yeast tRNA. The highest ribonucleolytic activity was demonstrated toward poly C, followed by poly A, and then by poly G. There was no activity toward poly U. The optimal pH for its activity was 7 and the optimal temperature was 55 degrees C. It inhibited cell-free translation in a rabbit reticulocyte lysate with an IC50 of 0.33 nM.
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Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
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D000595:Amino Acid Sequence; D008969:Molecular Sequence Data; D020076:Pleurotus / Q000201:enzymology* / Q000254:growth & development; D011131:Polyribonucleotides / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism; D012260:Ribonucleases / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism*; D017385:Sequence Homology
D011131:Polyribonucleotides; D012343:RNA, Transfer; D012260:Ribonucleases