结核潜伏感染相关蛋白Rv3407结构和功能的生物信息学分析

Bioinformatic analysis of the structure and function of the latent tuberculosis infection-related protein Rv3407

目的应用生物信息学方法预测分析结核潜伏感染相关蛋白Rv3407的结构及功能。方法从NCBI数据库中搜索结核分枝杆菌Rv3407蛋白的氨基酸序列,分别利用ProtParam、Protscale、TMHMM、PSORT、SignalP、ITASSER、NetNGlyc、NetPhos、Motif Scan、SOPMA、SWISS-MODEL等生物信息学软件分析蛋白质的理化性质、亲(疏)水性、跨膜螺旋、亚细胞定位、信号肽,可能与之结合的配体和该配体的结合位点、糖基化、磷酸化和翻译后修饰位点及二、三级结构;采用BepiPred、ABCpred、IEDB预测分析B细胞表位,采用SYFPEITHI、RANKPEP、NetMHC、NetCTL预测分析细胞毒性T淋巴细胞(CTL)表位,采用SYFPEITHI和RANKPEP预测分析辅助性T(Th)淋巴细胞表位。结果 Rv3407蛋白共由99个氨基酸构成,分子式为C471H807N155O144S2,不稳定指数为46.59,为亲水性不稳定蛋白;无跨膜螺旋区及信号肽,细胞内定位为胞浆蛋白;可能与之结合的配体有4个;无糖基化位点;苏氨酸、丝氨酸磷酸化位点分别有2和4个;酰胺化、cAMP和cGMP依赖的蛋白激酶磷酸化、蛋白激酶C磷酸化、N-豆蔻酰化、酪蛋白激酶Ⅱ磷酸化的位点各1个;其二级结构中α-螺旋、β-折叠、β-转角、无规则卷曲分别占45.45%、11.11%、8.08%及35.35%;B细胞表位可能分布于28-36、50-54、68-71、78-86、96-99位氨基酸残基或其附近;CTL表位可能分布于57-65,40-48,87-95位氨基酸残基或其附近;Th表位主要集中分布于2-39、45-63、71-85位氨基酸残基或其附近。结论结核潜伏感染相关蛋白Rv3407存在多个潜在的B细胞及T细胞抗原表位,其中以T细胞抗原表位占优势,免疫原性良好,可为结核潜伏感染疫苗的研制、免疫学诊断等提供理论依据。

Objective To use bioinformatics to predict and analyze the structure and function of the latent tuberculosis infection-related protein Rv3407. Methods The amino acid sequence of the Rv3407 protein of Mycobacterium tuberculosis was obtained from the NCBI database,and its physicochemical properties,hydrophilicity(hydrophobicity),transmembrane helicesx,subcellular localization,signal peptides,possible binding ligands and binding sites of the ligand,glycosylation,phosphorylation,and post-translational modification sites,and secondary and tertiary structures were analyzed using ProtParam,Protscale,TMHMM,PSORT,SignalIP,I-TASSER,NetNGlyc,NetPhos,Motif Scan,SOPMA,SWISS-MODEL,and other bioinformatic software.cell epitopes were predicted using theby software BepiPred,ABCpred,and IEDB.Cytotoxic T lymphocyte(CTL)epitopes were predicted using the software SYFPEITHI,RANKPEP,NetMHC,and NetCTL.Helper T(Th)lymphocyte epitopes were predicted using the software SYFPEITHI and RANKPEP. Results The Rv3407 protein consists of 99 amino acids,its molecular formula is C471 H807 N155 O144 S2,its instability index is 46.59,and it is a hydrophilic uinstable protein.It had no transmembrane helix region or signal peptides,and it is a cytoplasmic protein.The Rv3407 protein may have 4 ligands,and no glycosylation sites;it had 2 threonine and 4 serine phosphorylation sites,amidation site,1 site for phosphorylation of cAMP and cGMP-dependent protein kinase,1 site for phosphorylation of protein kinase C,1 site for N-myristoylation,and 1 site for phosphorylation of casein kinase II site.In its secondary structure consisted of,α-helices(45.45% ),β-sheets(11.11%,),β-turns(8.08%),and random coils(35.35%).Its B cell epitopes may be located at or near amino acids 28-36,50-54,68-71,78-86,and 96-99,its CTL epitopes may be located at or near amino acids 57-65,40-48,and 87-95,and its Th epitopes were mainly found at or near amino acids 2-39,45-63,and 71-85. Conclusion The Rv3407 protein has many potential B-cell and Tcell epitopes(T cell epitopes were dominant)and good immunogenicity.These findings,can provide a theoretical basis for the development of vaccines and immunological diagnosis of latent tuberculosis infection.