刚地弓形虫抑制蛋白主要特性分析与抗原表位预测

Prediction of main characteristics and antigenic epitopes of profilin from Toxoplasma gondii

目的用生物信息学方法分析刚地弓形虫抑制蛋白（ T. gondii profilin, TgPRF）的主要特性与抗原表位，筛选该蛋白的T／B细胞联合抗原表位。方法利用NCBI上的ORF finder, Prot-Param, SignalP, TMHMM. MotifScan. WoLF PSORT, PSORT Ⅱ, SOPMA, Bcepred. SYFPEITHI.NetCTL等生物信息学在线分析程序．结合Gene Runner和DNAMAN等生物信息学软件．分析并预测TgPRF蛋白的开放阅读框、理化性质、信号肽、跨膜区、翻译后修饰位点、亚细胞定位、二级结构、表面可及性、可塑性、亲（疏）水性及T/B细胞抗原表位。结果TgPRF基因的开放式阅读框为492个碱基的核苷酸序列。TgPRF蛋白由163个氨基酸组成，相对分子质量为17555．2，分子式为C764H^1160N204O258S7，等电点为4．40，有4个表面可及性参数≥1．9的区域、5个亲水性参数得分≥1．9的区域、3个柔韧性参数得分≥2的区域、10个翻译后修饰位点、8个潜在B细胞抗原表位和3个T／B细胞联合表位。结论TgPRF蛋白有多个优势抗原表位．为后续弓形虫免疫保护性的研究提供理论指导。

Objective To predict the main characteristics of profilin from Toxoplasma gondii （TgPRF） and its T/B cel/epitopes using bioinformatics. Methods The open reading frame（ORF）, physical chemical properties, signal peptide, transmembrane domains, post-translational modification site, sub-cellular localization, secondary structure, surface accessibility, flexibility, hydrophilicity/hydrophobicity and T/B cell epitopes of TgPRF were analyzed and predicted by bioinformatics online analysis programs including ORF finder, Prot- Param, SignalP, TMHMM, MotifScan,WoLF PSORT, PSORT Ⅱ, SOPMA, Bcepred, SYFPEITHI, NetCTL, combining with bioinformatics software （Gene Runner and DNAMAN）. Results The open reading frame of TgPRF gene contained 492 bases and the protein was composed of 163 amino acids with listed characters： the molecular mass was 17 555.2, the molecular formula was C764HII60N2040258S7, the value of theoretical isoelectric point was 4.40. There were four zones with surface accessibility ≥ 1.9, five zones with hydrophilieity ≥ 1.9, three zones with flexibility ≥2, ten post-translational modification sites, eight potential B cell epitopes and three combined T/B cell epitopes. Conclusion TgPRF consists of the dominant antigen epitopes, that will provide a theoretical basis for further study on protective immunity of toxoplasma gondii.