结核分枝杆菌PPE2的生物信息学分析

Bioinformatics analysis of Mycobacterium tuberculosis PPE2

目的应用生物信息学软件预测分析结核分枝杆菌PPE2蛋白的结构与功能。方法从NCBI中获得PPE2序列及其编码基因序列,通过OFR Finder、ProtParam、ProtScaleon Expasy、TMHMM Sever v.2.0、SignalP 4.1 Sever、PSORT、NetPhos 3.1 Sever、BLAST、SOPMA、SWISS-MODEL、ABCpred、SYFPEITHI等工具预测分析PPE2编码蛋白的生物学结构与特性。结果PPE2蛋白由556个氨基酸组成,相对分子质量为56951.97×10~3,等电点4.78,为亲水性蛋白,无跨膜区域及信号肽;编码基因Rv0256c总长度为1671 bp,有10个开放阅读框架;PPE2蛋白有53个磷酸化位点,1个保守结构域;蛋白二级结构中α-螺旋占41.91%,β-折叠占11.33%,β-转角占3.96%,无规则卷曲占42.81%;有57个(得分>0.5)B细胞抗原表位和113个(得分>15)T细胞抗原表位。结论PPE2蛋白为亲水蛋白,具有潜在的T、B细胞抗原表位,可作为研发结核病疫苗的候选蛋白。

Objective To predict and analyze the structure and function of the Mycobacterium tuberculosis PPE2 protein by using various bioinformatics software.Methods PPE2 gene(Rv0256 c)and its coding sequence were obtained from NCBI.The ORF Finder was used to find the open reading frames of the Rv0256 c gene.ProtParam was used to analyze the physicochemical properties,and ProtScaleon Expasy was used to analyze the hydrophilicity of the PPE2 protein.The transmembrane regions,the signal peptides,the subcellular localizations and the phosphorylation sites of the protein were predicted by TMHMM Sever V.2.0,SignalP 4.1 Sever,PSORT and NetPhos 3.1 Sever.The BLAST tool was used to predict its conserved domain and homology.SOPMA and Swiss-Model were used to predict the secondary structure and 3 D model of the protein.ABCpred and SYFPEITHI were used to predict its T-cell and B-cell epitopes.Results PPE2 protein was composed of 556 amino acids with an isoelectric point of 4.78.It was a hydrophilic protein without transmembrane region and signal peptide.The coding gene Rv0256 c was 1671 bp in length and had 10 open reading frames.PPE2 protein had 53 phosphorylation sites and 1 conserved domain.In protein secondary structure,α-helix accounted for 41.91%,β-folding accounted for 11.33%,β-turning accounted for 3.96%,random crimping accounted for 42.81%.In the 3 D model,the QmeaDisCo global score was 0.64±0.07.There were 57 B cell epitopes(score>0.5)and 113 T cell epitopes(score>15)in the protein.Conclusion PPE2 protein is a water protein with potential T and B cell epitopes,which can be used as a candidate protein for developing tuberculosis vaccine.