结核分枝杆菌AccD5蛋白的生物信息学分析

Bioinformatic analysis of the AccD5 gene in Mycobacterium tuberculosis

目的应用生物信息学软件预测结核分枝杆菌AccD5基因编码蛋白的结构和功能。方法从NCBI数据库获取AccD5基本的基因信息;应用ProtParam软件预测AccD5蛋白的理化性质;利用SignaIP 4.1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;利用BepiPred 1.0Server和SYFPEITHI分析蛋白的B细胞及T细胞抗原表位。结果AccD5蛋白共548个氨基酸,分子式为C2621H4153N727O810S17,分子质量单位(Mr)为59.354 2×103,理论等电点为5.19,脂溶性系数为91.15,不稳定性指数为31.21,亲水性平均系数为-0.16,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37.23%、10.58%、22.81%和29.38%,预测的B细胞、CTL细胞抗原表位分别为14个和25个。结论生物信息学分析AccD5为稳定蛋白,含有潜在的B、T细胞抗原表位,为研发治疗结核新药提供了潜在靶标。

Objective To use bioinformatic software to predict the structure and function of the AccD5 gene of Mycobacterium tuberculosis. Methods Basic information on the AccD5 gene was obtained from the NCBI database.The software ProtParam was used to predict the physicochemical properties of the protein.SignaIP 4.1and TMHMM were used to analyze signal peptides and transmembrane regions.The online software ExPASy was used to predict the secondary and tertiary structure of the protein.BepiPred 1.0Server and SYFPEITHI were used to analyze its antigenic epitopes. Results The AccD5 protein of Mycobacterium tuberculosis.contained 548 amino acids and its molecular formula was C2621H4153N727O810S17,its molecular mass was 59.354 2×103,its isoelectric point was 5.19,its hydrophobicity index was91.15,its instability index was 31.21,and the average coefficient of hydrophilicity was-0.16.The protein was predicted to be a stable and hydrophilic protein.Its secondary structure consisted ofα-helixes（37.23%）,β-turns（10.58%）,β-folds（22.81%）,and random coils（29.38%）.Predicted B cell epitopes were located at residues 303-313,270-298,394-403,537-546,475-484,2-18,514-523,240-259,150-157,37-50,91-107,192-198,220-233,and349-354.CTL cell epitopes were located at residues 156-164,530-538,24-32,200-208,65-73,404-412,449-457,321-329,523-531,111-119,261-269,292-300,313-321,527-535,58-66,127-135,257-265,176-184,179-187,343-351,387-395,405-413,419-427,430-438,and 461-469. Conclusion Bioinformatic prediction indicated that the AccD5 protein was a stable protein,and this protein might be a potential target for research on the diagnosis of tuberculosis.