田鼠巴贝虫棒状体相关蛋白基因的筛选及生物信息学分析

A search for and bioinformatic analysis of genes coding for rhoptry-associated proteins of Babesia microti

目的通过对专业数据库的搜索,筛选出田鼠巴贝虫棒状体相关蛋白的基因,并进行生物信息学分析预测。方法搜索NCBI、EMBL-EBI、Uniprot及PiroplasmaDB数据库,筛选田鼠巴贝虫棒状体蛋白基因。通过生物信息学方法,利用多种数据库及生物信息学分析软件分析其对应氨基酸序列的疏水区、跨膜区、信号肽及结构域,预测该蛋白二级结构、三级结构及其抗原表位;利用Clustal-X软件对其氨基酸序列进行同源性比对;利用PAUP软件构建系统发育树,对氨基酸序列进行多重序列比对(mutiple sequence alignment)。结果在EMBL-EBI和PiroplasmaDB中各筛选出1条田鼠巴贝虫棒状体蛋白基因,登录号分别为XP_012649548和BBM_III04695。通过软件APE进行序列比对,两个基因序列完全一致,证明为同一条基因序列。该基因共含有4 443bp,可编码1 480个氨基酸。编码蛋白分子质量为165.307ku,为分泌蛋白,含一个信号肽,4个跨膜区,并含有较多抗原表位。结论采用生物信息学方法预测田鼠巴贝虫棒状体相关蛋白含有较多的抗原表位,可作为疫苗和诊断抗原的候选分子。

Objectives To search specialized databases in order to screen for genes coding for rhoptry-associated proteins （RAPs） of Babesia microti and to bioinformatically analyze and predict those genes. Methods The NCBI, EMBL, EBI, Uniprot, and PiroplasmaDB online databases for searched for target genes of B. microti. The hydrophobicity, transmembrane domains, signal peptides, and protein domains of the protein coded for by this gene were analyzed, the secondary and tertiary structure of that protein, and the antigen epitope were also predicted. Blast analysis of amino acid sequence homology was performed with Clustal X and a phyiogenetie tree was constructed with the software PAUP. Results Sequences of RAP genes of B. microti were screened against the EMBI. EBI and PiroplasmaDB database, yielding genes with the accession numbers XP_012649548 and BBM_III04695. Comparison with the software APE revealed that the sequences matched. The gene consisted of 4,143 bp and encoded 1 480 amino acids. The encoded protein had a molee ular weight of 165. 307 ku. The protein contains a signalpeptide, four transmembranedomains （7 29, 1 256-1 278, 1 377-1 399, and 1 414 -1 433aa）. The identified RAP orB. microtiis probablya stable, secreted protein withmuhiple epitopes. Phylogenetic analysis of the sequence of RAP indicated that B. microti is closely related to other species of Babesia and distinct from other genera of parasites. The sequence of the RAP of B. microti was 68% similar to the RAP of B. bowls and 67% similar to the RAP of B. divergens. Conclusion An RAP of B. microti was identified by search ing specialized databases. This protein has multiple epitopes and could be used as a potential vaccine and diagnostic anti gen.