Flammin and velin: new ribosome inactivating polypeptides from the mushroom Flammulina velutipes.
A protein designated flammin and exhibiting a molecular mass of 30kDa, and another protein designated velin and possessing a molecular mass of 19 kDa, were isolated from the fruiting bodies of the edible mushroom Flammulina velutipes. Flammin and velin inhibited translation in a rabbit reticulocyte lysate system with an IC(50) of 1.4 and 2.5 nM, respectively. Flammin demonstrated only a small degree of resemblance in N-terminal sequence to angiosperm type 1 ribosome inactivating proteins (RIPs) such as trichosanthin, alpha-momorcharin and beta-momorcharin but no sequence similarity to other mushroom RIPs. Velin manifested limited sequence homology to the A chain of abrin, a type 2 angiosperm RIP. Neither flammin nor velin showed any ribonuclease or protease activity. Both flammin and velin were unadsorbed on DEAE-cellulose and adsorbed on Affi-gel blue gel and CM-Sepharose. They were separable in gel filtration on Superdex 75 by fast protein liquid chromatography.
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Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. b021770@mailserv.cuhk.edu.hk
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D000363:Agaricales / Q000737:chemistry*; D000595:Amino Acid Sequence; D005656:Fungal Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D008969:Molecular Sequence Data; D011500:Protein Synthesis Inhibitors / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D012270:Ribosomes / Q000187:drug effects*
D005656:Fungal Proteins; D011500:Protein Synthesis Inhibitors