中文摘要：

采用定点突变技术改造杀虫晶体蛋白，是提高其杀虫活性的有效途径，但目前在突变位点和氨基酸种类的选取上还存在很大的盲目性。以杀小菜蛾活性明确的23个杀虫晶体蛋白上的4个关键结构域为研究对象，用主成分分析法处理20种氨基酸1369种性质参数后的第一个主成分的得分向量来表征氨基酸差异，实现序列数据化。通过逐步回归找到了6个关键氨基酸位点：X3、X9、X12、X13、X14和x19，并进一步通过偏最小二乘二次多项式回归寻根最优氨基酸残基L／X3、S／X9、S／X12、T／X13、A，）（14和G／X19，从而建立了杀虫晶体蛋白的序列特征与其杀小菜蛾活性间关系的定量模型。这有助于快速地预测出有利于提高杀小菜蛾活性的氨基酸位点和种类，从而提高定点突变改造杀虫晶体蛋白的效率。

英文摘要：

The knowledge of the relationship between sequence characteristics of insecticidal crystal proteins （ICP） and their inhibitory against Plutella xylostella provided helpful information for the rational design of ICP with desirable activity against Plutella xylostella.The four key loops of ICP with determined activities against Plutella xylostella were selected to study the quantitative relationship between sequence characteristics and insecticidal activity. The first principle components＇ score vectors for 20 amino acids were assigned to converting amino acids into data. The six key sites X3, X9, X12, X13, X14 and X19 were predicted by stepwise regression method. The amino acids L/X3, S/X9, S/X12, T/X13, A/X14 and G/X19 found by partial least squares regression and second order polynomial models were predicted to increase the activity of ICP against Plutella xylostella.