结核分枝杆菌PhoP蛋白的生物信息学分析

Bioinformatic analysis of the PhoP in Mycobacterium tuberculosis

目的应用生物信息学软件预测结核分枝杆菌PhoP基因编码蛋白的结构和功能。方法从NCBI数据库获取PhoP基本的基因信息及其编码序列氨基酸信息;应用ProtParam软件预测PhoP蛋白的理化性质;利用SignalIP4.1和TMHMM分析其信号肽和跨膜区;利用在线分析Expasy工具分析蛋白二级结构,建立蛋白三级结构模型;采用Bepipred 1.0Server和SYFPEITHI分析蛋白的B细胞及T细胞抗原表位。结果 PhopP蛋白共250个氨基酸,分子式为C1226H1974N346O364S4,原子总数3 914,半衰期为30h,预测该蛋白为稳定性亲水性蛋白;二级结构中α-螺旋、β-转角、β-折叠、无规则卷曲分别占36.03%、10.58%、24.7%和27.94%,预测的B细胞、CTL细胞抗原表位分别为21个和7个;PhoP基因与天蓝色链霉菌同源性较高;其编码蛋白的相互作用蛋白为PhoR、senX3、trcS等。结论生物信息学分析PhoP为稳定蛋白,且含有潜在的B、T细胞抗原表位,是结核病诊断及治疗的潜在候选因子。

Objective To use bioinformatic software to predict the structure and function of the protein coded for by the PhoP gene of Mycobacterium tuberculosis. Methods Information on the PhoP gene and the amino acid sequences it codes for were obtained from the NCBI database.The software ProtParam was used to predict the physico-chemical properties of the PhoP protein.SignalIP4.1 and TMHMM were used to analyze signal peptides and transmembrane regions.The secondary structure of the protein was analyzed using Expasy,and a model of the protein’s tertiary structure was created.B-cell and T-cell epitopes were analyzed using BepiPred 1.0 Server and SYFPEITHI. Results The PhoP protein consisted of 250 amino acids,its molecular formula was C1226 H1974 N346 O364 S4,it contained 3 914 atoms in total,and its half-life was 30 h.The protein was predicted to be a stable hydrophilic protein.The secondary structure consisted ofα-helices（36.03%）,β-turns（24.7%）,andβ-sheets（27.94%）.The protein was predicted to have 21 B-cell epitopes and7 CTL epitopes.The PhoP gene of M.tuberculosis is highly similar to that of Streptomyces coelicolor.The interacting proteins were PhoR,senX3,and trcS. Conclusion The results of bioinformatic analysis suggested that PhoP is a stable protein and that it contains potential B-and T-cell epitopes.The protein is a potential screening factor for diagnosis and treatment of tuberculosis.