Purification And Partial Characterization Of An Antiviral Protein From The Maitake

A protein inhibitor of Tobacco mosaic virus infection on Nicotiana glittinosa, named GFAP, was isolated and purified to homogeneity from the fruiting bodies of edible fungus maitake(Gn/o/a frondosd) by precipitation of (NH4)2SO4 followed by DEAE-Sepharose and Sepharose-6B column chromatography. The protein showed homogeneity on the native polyacrylamide gel electrophoresis and isoelectric focusing electrophoresis. We studied its characterization and activity of inhibiting TMV infection. Antiserum was prepared by immunizing rabbit with GFAP, which was further purified by PAGE. GFAP was shown to have moderate thermal stability. The inhibition of TMV was about 80% after GFAP was heated at 80 癈 for 10 min in a temperature controlled water bath. The isoelectric point of GFAP is 3.67. GFAP is a glycoprotein containing 2% sugar. A 34kD protein band and a 40kD protein band were observed consistently by SDS-PAGE. The N-terminal sequence of 40kD protein band was ACCVPSVTEFENAINSDPVM. Compared with the protein sequence of the GenBank, we found no homologous sequence with it. It indicates that the protein is a new protein. At a concentration of 32 g /ml of GFAP, the formation of local lesions on Nicotiana glutinosa leaves caused by 10ug /ml TMV infection was completely inhibited and at 4ug /ml GFAP, 63.9% inhibition was obtained by 40ug /ml TMV. GFAP can't induce systemic resistance on Nicotiana tabacum and can't inhibit the multiplication and movement of TMV on Nicotiana tabacum. On potato-sucroseager medium, the purified protein did not inhibit the growth of three plant pathogen fungus, Botrytis cinerea, Fusarium oxysporum and Colletotrichum piperatum. And GFAP did't inhibit the growth of a plant pathogen bacteria, Ralstonia solanacearum, on NA medium.