棉铃虫类胰蛋白酶的生物信息学分析

Bioinformatics Analysis of Putative Trypsins of Helicoverpa armigera

对棉铃虫(Helicoverpa armigera L.)肠道内7种类胰蛋白酶的氨基酸序列进行了生物信息学分析。结果表明,棉铃虫7种类胰蛋白酶理化性质相近,含有丰富的Ala、Cys、Gly与Thr,均为可溶性蛋白酶,不稳定性较高。类胰蛋白酶分子中不存在跨膜结构域,含有特定的磷酸化位点,主要分布在细胞外基质与内质网中。棉铃虫类胰蛋白酶属于胰蛋白酶超家族成员,具有较高的氨基酸序列同源性,分子中含有保守的必需氨基酸残基,参与维持蛋白酶的空间结构及行使催化功能。分子进化研究表明类胰蛋白酶Ⅲ与类胰蛋白酶Ⅵ进化关系较近,而类胰蛋白酶Ⅰ和类胰蛋白酶Ⅱ在进化关系上更为接近。无规卷曲结构是类胰蛋白酶二级结构中的主要结构元件。

Bioinformatic methods were used to analyze the amino acid sequences of 7 putative trypsins in the midgut of Helicoverpa armigera. The results showed that physical and chemical characteristics of these trypsins were very similar. Ala,Cys,Gly and Thr were abundant in these trypsins. These trypsins were soluble and relatively instable. They had no transmembrane structure and each trypsin had specific phosphorylation sites. They were mainly located in the extracellular and endoplasmic reticulum. These trypsins were belonged to the trypsin super family with highly homologous amino acid sequences. These trypsins consisted conservative residues participated in maintaining tertiary structure and catalytic process. Phylogenetic tree analysis showed that trypsin Ⅲ was similar to trypsin Ⅵ,and trypsin Ⅰ was more close to trypsin Ⅱ. Random coils were the major element in the whole secondary structure of these trypsins.