枯草芽孢杆菌Tpb55分离自烟草叶围,对烟草赤星病菌具有较强的拮抗能力.除去菌体培养液以90%饱和度硫酸铵沉淀所得的拮抗粗提液对热稳定,在pH为5.0-10.0范围内较稳定,对木瓜蛋白酶,蛋白酶K,胃蛋白酶不敏感.粗提液经DEAE Sepharose Fast Flow离子交换层析和Sephadex G-75 (1.6 cm×80 cm)凝胶层析,纯化出一种抗菌蛋白,采用聚丙烯酞胺凝胶电泳对蛋白分子量测定,该抑菌蛋白分子量约为47.8 kD,自动Edman降解法从Bst1N端测得的氨基酸序列为:Met-Glu-Ee-Phe-Lys-Tyr-Met-Glu-Thr-Tyr-Asp-Tyr-Glu-Gln-Leu-Val-Phe-Cys-.%Bacillus subtilis Tpb55, an antagonistic bacteria isolated from the phyllosphere of tobacco, strongly inhibits the growth of Alternaria alternata (Fries) Keissler, which causes the tobacco brown spot. Crude extract was obtained by precipitation of the cell-free culture of Tpb55 with 90％ saturated (NH4)2SO4. The suspension of the precipitate strongly inbibits Alternaria alternata (Fries) Keissler, and it is thermostable, resistant to trypsin, proteinase K, pepsin and organic solvent. Its active pH range is wide, from 5.0 to more than 10.0. One antagonistic peak was obtained from the crude extract of Tpb55 after DEAE-sepharose Fast Flow and Sephadex G-75, which was shoed only single band with 47.8 kD and PI7.2 in SDS-PAGE, respectively. Analyzed the N-terminal partial sequence of protein was Met-Glu-Ile-Phe-Lys-Tyr-Met-Glu-Thr-Tyr-Asp-Tyr-Glu-Gln-Leu-Val-Phe-Cys-.
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