苏云金芽胞杆菌杀虫晶体蛋白Cry7Ba1溶解性改良

苏云金芽胞杆菌杀虫晶体蛋白Cry7Ba1需要在强碱性缓冲液中(pH12.5)才能溶解，而且只有溶解后才能表现出毒力。分别用Cry1Ac和Cry1C晶体蛋白的C-半段替换Cry7Ba1的C-半段，结果发现当Cry7Ba1的C-半段被替换后，重组晶体蛋白与Cry1Ac和Cry1C等其它晶体蛋白一样在弱碱性条件下(pH9.5)能有效溶解，而且其杀虫活性没有发生明显变化。本研究结果表明Cry7Ba1晶体蛋白难溶的特性是由其C-半段结构决定的，通过改变其C-半段结构改善溶解性，为该晶体蛋白的应用提供了可能。

Improvement of Solubility of Cry7Ba1Crystal from Bacillus thuringiensis

The crystal consisting of Cry7Ba1 crystal protein from Bacillus thuringiensis could be dissolved only at pH values of >11.5, and did not exhibit toxicity while it was not dissolved. In this study, the C-terminal half of Cry7Ba1 were replaced by that of Cry1C and Cry1Ac, respectively. The results indicated that, when the C-terminal half of Cry7Ba1 was substituted, the crystal formed by the recombinant crystal proteins could be dissolved in alkaline buffer (pH9.5) as that of Cry1Ac and Cry1C did, and the toxicity has not be changed. These data suggested that the property of insolubility of Cry7Ba1 crystal was associated with the structure of C-terminal half. This research could improve the solubility through swapping the C-terminal half of Cry7Ba1, and supplied possibility for the crystal protein biocontrol application.