结核分枝杆菌LepB蛋白的功能预测及生物信息学分析

Bioinformatic analysis of the LepB protein from Mycobacterium tuberculosis and prediction of its function

目的应用生物信息学方法预测分析结核分枝杆菌Rv2903c基因编码蛋白LepB的结构与功能。方法在GenBank数据库中获取Rv2903c的基因信息;运用ProtParam及ProtScale预测其编码LepB蛋白的理化性质及亲疏水性;应用NetPhos、TMHMM、MotifScan分析LepB的磷酸化位点、跨膜区及翻译后修饰位点;分别利用SOPMA、SWISS MODEL分析LepB蛋白的二级结构并建立三级结构模型;利用Bepired、BCpred及SYFPEITHI、NetMHCIIpan预测LepB蛋白的B细胞与T细胞表位。结果 Rv2903c编码的LepB蛋白含有294个氨基酸残基,亲水系数-0.230,为亲水性蛋白。LepB含有21个磷酸化位点,存在一处跨膜区域,二级结构以无规则卷曲为主(占55.1%),结构较疏松,利用SWISS-MODEL建构建出LepB蛋白的三级结构。LepB蛋白含有9个B细胞抗原表位。结论 LepB蛋白是结核分枝杆菌的信号肽酶,切割完成蛋白质分泌的信号肽。生物信息学预测LepB是跨膜蛋白,含有多个抗原表位,可作为结核治疗的潜在分子靶标。

Objective To use bioinformatics to analyze and predict the structure and function of LepB,which is a protein coded for by the Rv2903 cgene of Mycobacterium tuberculosis. Methods Basic information on the Rv2903 cgene was obtained from the GenBank database.ProParam and ProtScale were used to predict the physicochemical properties and hydrophobicity of the LepB protein.NetPhos,TMHMM,and MotifScan were used to analyze its phosphorylation sites,transmembrane regions,and post translational modification sites.SOPMA and SWISS MODEL were used to analyze its secondary structure and to model its tertiary structure.BepiPred,BCpred,SYFPEITHI,and NetMHCIIpan were used to predict its B-and T-cell epitopes. Results The LepB protein coded for by the Rv2903 cgene contains 294 amino acid residues,it has a hydrophilicity index of-0.230 and is a hydrophilic protein.The LepB protein contains 21 phosphorylation sites and has a transmembrane structure.The secondary structure mainly consisted of random coils（55.1%）.The structure is loose packed.The tertiary structure was modeled using SWISS-MODEL.The LepB protein has 9 potential B-cell epitopes. Conclusion The LepB protein is the signal peptidase of M.tuberculosis,and this enzyme cleaves the signal peptide secreted by the protein.Bioinformatics predicted that LepB is a transmembrane protein,that it contains multiple antigenic epitopes,and that it can potentially serve as a molecular target for tuberculosis therapy.