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研究了苏云金芽胞杆菌(Bacillus thuringiensis,Bt)Cry7Bal的C-端半胱氨酸(Cys)在溶解性改良过程中的作用。本实验通过定点突变将Cry7Bal的C-端834和854位的Cys突变成丝氨酸(Ser),SDS-PAGE和镜检结果表明两个突变体在蛋白表达和晶体形成方面与Cry7Bal没有显著差别;溶解性实验结果表明C854S可以在pH 11.5时很好地溶解,C834S可以在pH9.5时很好地溶解。本研究通过对Cry7Bal的C-端单个半胱氨酸的突变,提高了Cry7Bal的溶解性。这为恢复Cry7Bal晶体蛋白的杀虫活性提供了可能性,也为这一类由于不能溶解而发挥不出活性的Cry蛋白的应用提供了新的思路。
The role of Cys in Cry7Bal of Bacillus thuringiensis (Bt) in solubility improvement was investigated. In this experiment, the Cys of Cry7Bal at the C-terminal 834 and Cys 854 were mutated to Ser by site-directed mutagenesis. The results of SDS-PAGE and microscopic examination showed that the two mutants did not differ significantly from Cry7Bal in protein expression and crystal formation. Solubility test results show that C854S can dissolve well at pH 11.5 and C834S can dissolve well at pH 9.5. In this study, the mutation of Cry7Bal C-terminal single cysteine increased the solubility of Cry7Bal. This provides the possibility of restoring the insecticidal activity of Cry7Bal crystal protein and also provides a new idea for the application of Cry protein which can not exert its activity due to insolubility.