亚洲带绦虫成虫谷胱甘肽S-转移酶基因的克隆及生物信息学分析

目的分析亚洲带绦虫成虫谷胱甘肽S-转移酶（GST,glutathione S-transferase）基因结构并预测其编码蛋白的结构和功能。方法利用生物信息网站如美国国家生物技术信息中心（NCBI,http：//www.ncbi.nl m.nih.gov/）和瑞士生物信息学研究所的蛋白分析专家系统（ExPASY,http：//ca.expasy.org/）中生物信息学分析工具,并结合其它分析软件,从获得亚洲带绦虫成虫全长cDNA质粒文库的表达序列标签（EST,expression sequence tag）中识别GST基因,分析该基因的结构并预测其编码的蛋白质的结构和功能特征。结果该基因与猪带绦虫GST的一致性为94%,相似性为97%;全长810bp,编码区为28-687bp,编码219个氨基酸,无各种亚细胞定位序列,具有多个潜在的磷酸化位点,蛋白的理化性质稳定;预测三个主要的抗原表位89aa-94aa,27aa-32aa,119aa-124aa位于空间结构上相距较远的分子表面,前面两个表位属于绦虫共有的线性抗原表位。结论从亚洲带绦虫成虫cDNA文库中筛选出GST基因,预测为胞浆型蛋白,可能具有较好的免疫诊断抗原应用前景。

Cloning and bioinformatics analysis of cDNA encoding a novel glutathione S-transferase from Taenia asiatica

In order to analyze and predict the structural characteristics of glutathione S-transferase from Taenia asiatica by bioinformatics,a full-length cDNA sequence encoding glutathione S-transferase was identified from full-length cDNA plasmid libratory of Taenia asiatica by using the bioinformatics tools in bioinformatics webs site such as NCBI(http://www.ncbi.nlm.nih.gov/),ExPaSy(http://www.expasy.org/)and some else software packages of bioinformatics.The cDNA sequence was analyzed and the characteristics of its deduced protein including physical-chemical characteristics,epitopes,modification sites after translation,conserved domains,subcellular location,topological structure,the second and the three dimensional(3D)structure were predicted.The location of epitopes in predicted 3D structure of glutathione S-transferase was determined.It was demonstrated that the identity and positive rates between the amino acids sequence deduced by the cDNA sequence and that of glutathione S-transferase from Taenia solium are 94% and 97% respectively.This novel cDNA sequence contained 810bp with a putative open reading frame of 291 amino acids.The protein with stable physical-chemical characteristics had no transmembrane region and sequence for subcellular location.Three major linear epitopes of glutathione S-transferase was predicted to locate from 89 aa to 94 aa,27 aa to 32 aa and 119 aa to 124 aa.These three eiptopes were far away from each other on the surface of spatial structure of glutathione S-transferase,and two of which were consensus linear epitopes of other tape worms.In the present work,the full-length cDNA of Glutathione S-transferase was screened from the cDNA library of adult Taenia asiatica by bioinformatics method.It suggests that glutathione S-transferase of Taenia asiatica is predicted to be a cytosolic protein and a potential molecule for immunodiagnosis.