Abstract：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.
