苏云金芽孢杆菌cry1Ea基因的克隆及生物信息学分析

Cloning and Bioinformatics analysis of a cry1Ea-type gene from Bacillus thuringiensis

不同来源的苏云金芽孢杆菌能产生多种多样的晶体(Cry)蛋白。基于这个特性,人们可以通过基因工程的手段向工程菌中转入编码多种Cry毒素的基因来控制虫害。通过DNA重组技术,从BtHZM2菌株中克隆出了cry1Ea基因,对其进行了生物信息学分析,同源比对结果表明,cry1Ea8基因的核苷酸序列与已知cry1Ea的同源性为99.77%～99.91%,对应的氨基酸序列同源性为99.49%～99.74%。对cry1Ea8基因的分析还揭示出了cry1Ea8及其编码蛋白的一些生物和理化性质。结构域预测表明,Cry1Ea8由3个结构域组成,其中N-末端螺旋状结构域与膜插入与孔隙形成有关,而第二和第三个结构域与受体的结合有关。该研究为转基因抗虫植物和微生物杀虫工程菌的构建提供了新的基因来源。

Different isolates of the soil bacterium Bacillus thuringiensis produce muhiple crystal （Cry） proteins toxic. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. A cry1Ea-type gene, designated cry1Ea8, was cloned from the etrain Bt HZM2, through the recombinant DNA technology. Nuclcotide sequencing for the cry1Ea6 gene is 99.49% -99.74% identical to the known crylEa gene. Homology comparison revealed that the deduced amino acid sequence of Cry1Ea8 had an identity over 99% with those of the known crylEa proteins. Domain Analysis showed that there were three domains in Cry1Ea8. N-terminal spiral domain was responsible for membrane insertion and pore-forming of the toxin and the other two domains was relevant to the receptor binding. It provided new selection for development of novel Bt products based on its toxins.