目的应用生物信息学技术预测曼氏迭宫绦虫线粒体载体蛋白超家族的结构和功能,为进一步研究曼氏迭宫绦虫的蛋白质提供理论依据。方法将测得的曼氏迭宫绦虫成虫EST序列用ORF finder获取开放读码框,Blast进行分析其结构域。应用分析工具Protparam、InterProScan、protscale、SignalP-3.0、PSORTⅡ、BepiPred、TMHMM、VectorNTI Suite 9软件包、Phyre2分别进行该蛋白质的基本性质、结构域、疏水性、信号肽、亚细胞定位、抗原表位、跨膜区及空间结构的预测及分析。结果 Blast预测该蛋白质为线粒体载体蛋白超家族,保守功能域为线粒体二羧酸载体,含294个氨基酸残基,理论分子量为32132.2Da。与曼氏血吸虫进化地位最接近;有1个信号肽位点和6个潜在的抗原表位。结论曼氏迭宫绦虫线粒体二羧酸载体能够介导苹果酸、琥珀酸等二羧酸的转运,使其跨越线粒体膜参与三羧酸循环,为虫体自身提供能量,可能是潜在的疫苗候选分子及药物作用靶点。
Objective:To identify full length cDNA sequence of lactate dehydrogenase(LDH) from adult Echinococcus granulosus(E.granulosus) and to predict the structure and function of its encoding protein using bioinformatics methods.Methods:With the help of NCBI,EMBI, Expasy and other online sites,the open reading frame(ORF),conserved domain,physical and chemical parameters,signal peptide,epitope,topological structures of the protein sequences were predicted and a homology tertiary structure model was created:Vector NT1 software was used for sequence alignment,phylogenetic tree construction and tertiary structure prediction. Results:The target sequence was 1 233 bp length with a 996 bp biggest ORF encoding 331 amino acids protein with typical L-LDH conserved domain.It was confirmed as full length cDNA of LDH from E.granulosus and named as EgLDH(GenBank accession number:HM748917).The predicted molecular weight and isoelectric point of the deduced protein were 3 5516.2Da and 6.32 respectively.Compared with LDHs from Taenia solium,Taenia saginata asiatica,Spirometra erinaceieuropaei.Schistosoma japonicum,Clonorchis sinensis and human,it showed similarity of 86% ,85% ,55% ,58% ,58% and 53% ,respectively.EgLDH contained 3 putative transmembrane regions and 4 major epitopes(54aa-59aa.81aa-87aa,97aa-102aa,307aa-313aa),the latter were significant different from the corresponding regions of human LDH.In addition,some NAD and substrate binding sites located on epitopes 54aa-59aa and 97aa-102aa,respectively.Tertiary structure prediction showed that 3 key catalytic residues 105R,165D and 192H forming a catalytic center near the epitope 97aa-102aa,most NAD and substrate binding sites located around the center.Conclusions:The full length cDNA sequences of EgLDH were identified.It encoded a putative transmembrane protein which might be an ideal target molecule for vaccine and drugs.
Gang LuYajun LuLihua LiLixian WuZhigang FanDazhong ShiHu WangXiumin Han
目的:构建细粒棘球绦虫(E.g.)成虫全长cDNA质粒文库,并检测文库质量。方法:提取E.g.成虫mRNA,应用SMART方法构建pBluescript II SK全长cDNA质粒文库,检测文库的重组率及容量;用载体克隆位点两端的引物进行PCR扩增,检测插入片段大小。随机挑选阳性重组克隆5′端测序,归并unigene,计算unigene得率,全长性判定主要根据同源全长基因5'末端进行比较判定并计算全长率。结果:成功构建E.g.成虫全长cDNA质粒文库。文库的重组率为95.04%,库容量1.13×106;平均插入片段长度约为1.2 kb。24个随机阳性克隆测序,unigene比例为69.57%,全长性比率为64.71%。结论:成功构建E.g.成虫全长cDNA质粒文库,文库质量良好。
