结核分枝杆菌PpiA蛋白的生物信息学分析及功能预测

Bioinformatic analysis of the PpiA protein from Mycobacterium tuberculosis and prediction of its function

目的应用生物信息学方法对结核分枝杆菌Rv0009基因编码蛋白PpiA的结构与功能进行预测和分析。方法由NCBI数据库中获得Rv0009基因及PpiA蛋白的相关序列信息;运用ProtParam及ProtScale对PpiA蛋白的理化特性和亲疏水性进行分析;运用NetPhos、TMHMM分析PpiA的磷酸化位点及跨膜区结构;分别运用SOPMA、SWISS-MODEL、ABCpred预测PpiA蛋白的二级结构和三级结构;运用SYFPEITHI软件进行抗原表位的预测分析;运用STRING预测PpiA的相互作用蛋白,并对其生物过程进行功能富集分析。结果结核分枝杆菌蛋白PpiA由182个氨基酸组成,分子式为C848H1310N238O267S4,属于稳定的亲水性蛋白;其二级结构中无规则卷曲(Cc)含量占53.85%,α-螺旋(Hh)含量占18.68%,β-折叠(Ee)占20.88%,β-折角(Tt)含量占6.59%。PpiA蛋白无信号肽和跨膜区结构,具有14个磷酸化优势位点;该蛋白含有18个B细胞抗原优势表位以及3个CTL细胞抗原优势表位,其互作蛋白分别为groEL2、groEs、TB18.6、dnak、tpx和tur等,并参与多种生物学过程。结论生物信息学分析PpiA蛋白具有良好的抗原优势表位和氨基酸磷酸化位点,参与分子伴侣介导的蛋白质折叠、抵抗压力以及应激调节等生物学过程,是探索结核分枝杆菌持久性感染机制的重要研究靶标。

Objective To predict and analyze the structure and function of the Rv0009 gene encoding the protein PpiA in Mycobacterium tuberculosis.Methods Sequence information on the Rv0009 gene and PpiA protein were obtained from the NCBI database.ProtParam and ProtScale were used to predict the basic physicochemical properties and hydrophobicity of the PpiA protein.The phosphorylation sites and transmembrane structures of PpiA were analyzed using NetPhos and TMHMM,and SOPMA and SWISS-MODEL were used to predict the secondary and tertiary structures of the PpiA protein.ABCpred and SYFPEITHI were used to predict epitopes of the PpiA protein.The interaction proteins of the PpiA protein were predicted using STRING,and its biological process were identified using enrichment analysis.Results The PpiA protein in M.tuberculosis consisted of 182 amino acids.Its molecular formula was C848H1310N238O267S4.Analysis of the secondary structure indicated that it consisted of random coils(Cc,53.85%),α-helices(Hh,18.68%),β-sheets(Ee,20.88%)andβ-turns(Tt,6.59%).The PpiA protein has no signal peptides or transmembrane structures,and it has 14 phosphorylation dominant sites.The protein is predicted to have 18 B-cell dominant epitopes and 3 CTL cell dominant epitopes.The PpiA protein interacts with groEL2,groEs,TB18.6,dnak,tpx,tur,and other proteins,and it participates in various biological processes.Conclusion Bioinformatic analysis indicated that the PpiA protein in M.tuberculosis has B-cell and T-cell epitopes and amino acid phosphorylation sites.It participates in molecular chaperone-mediated protein folding,stress resistance,stress regulation,and other biological processes.This protein is an important research target to explore the mechanism of persistent infection with M.tuberculosis.