刚地弓形虫CDPK1蛋白结构与抗原表位的生物信息学分析

Bioinformatics analysis of the structure and antigenic epitopes of Toxoplasma gondii CDPK1 protein

目的对刚地弓形虫钙依赖性蛋白激酶1(Toxoplasma gondii Calcium-dependent protein kinases1,TgCDPK1)的蛋白结构及抗原表位进行分析,为弓形虫病疫苗的研制提供参考依据。方法在NCBI数据库中检索TgCDPK1蛋白的氨基酸序列,分别采用ProtParam、ProtScale、MotifyScan、TMHMM 2.0、SMART、SOPMA、Phyre2、IEDB、PSORT、STRING、PREDICTED ANTIGENIC PEPTIDES及SYFPEITHI在线分析网站预测TgCDPK1蛋白的氨基酸组成、理化性质、蛋白翻译后修饰位点、结构域、功能域、二级结构、三级结构、互作蛋白、抗原决定簇、B细胞抗原表位及T细胞抗原表位等。结果TgCDPK1蛋白由582个氨基酸组成,其分子式是C_(2898)H_(4573)N_(785)O_(888)S_(25),分子质量单位(Mr)为65.42142×10^(3),理论等电点为6.04,不稳定指数为36.980,脂溶性指数为79.91;该蛋白存在36个蛋白翻译后修饰位点;不含跨膜结构域,但含4个EF-手钙结合域及1个蛋白激酶结构域;蛋白二级结构中52.96%为α-螺旋,14.00%为延长链,7.90%为β-转角,35.05%为无规则卷曲;共含24个抗原决定簇,平均抗原倾向指数为1.0237;TgCDPK1蛋白抗原表位分布广泛,含有8个B细胞抗原表位、14个CTL细胞表位和12个Th细胞表位。结论TgCDPK1蛋白含有多种抗原表位,免疫原性高,可作为弓形虫病疫苗研制的候选蛋白。

Objective The protein structure and antigenic epitopes of Toxoplasma gondii Calcium-dependent protein kinases1(TgCDPK1)were analyzed to provide a reference for the development of a vaccine against toxoplasmosis.Methods Searched the amino acid sequence of TgCDPK1 protein in NCBI database and respectivelyused ProtParam,ProtScale,MotifyScan,TMHMM 2.0,SMART,SOPMA,Phyre2,IEDB,PSORT,STRING,PREDICTED ANTIGENIC PEPTIDES and SYFPEITHI online analysis website to predict the amino acid composition,physicochemical properties,post-translational modification sites,structural domains,functional domains,secondary structure,tertiary structure,interacting proteins,antigenic determinants,B-cell antigenic epitopes,and T-cell antigenic epitopes of TgCDPK1 protein.Results The TgCDPK1 protein consists of 582 amino acids,with a molecular formula of C_(2898)H_(4573)N_(785)O_(888)S_(25),a molecular mass unit(Mr)of 65.42142×10^(3),a theoretical isoelectric point of 6.04,an instability index of 36.980,a lipid solubility index of 79.91,and a bulk average hydrophilicity of-0.414.The protein exists 36 protein post-translational modification sites;does not contain transmembrane structural domains,but contains four EF-hand calcium-binding domains and one protein kinase structural domain.The protein secondary structure contains 52.96%alpha-helices,14.00%extended strands,7.90%beta-turns,and 35.05%irregular coilshas;it has a 60.90%probability of localizing in the cytoplasm.In addition,the protein has a total of 24 antigenic determinants,the average antigenic propensity index is 1.0237.The antigenic epitopes of TgCDPK1 protein are widely distributed,containing 8 B-cell antigenic epitopes,14 CTL cellular epitopes and 12 Th-cellular epitopes.Conclusion The TgCDPK1 protein contains a variety of antigenic epitopes,which are highly immunogenic and can be used as a candidate protein for toxoplasmosis vaccine development.