结核分枝杆菌MazF5毒素蛋白的生物信息学分析

Bioinformatics analysis of the Mycobacterium tuberculosis MazF5 toxin protein

目的 探究结核分枝杆菌MazF5蛋白的结构与功能。方法 从NCBI数据库获得编码MazF5基因信息及氨基酸的序列;运用Expasy的ProtParam应用插件分析蛋白理化性质;运用ProtScale、SignalP 4.1、TMHMM Serverv.2.0、NetPhos 3.1、YinOYang 1.2软件分别预测蛋白的亲疏水性、信号肽、跨膜区、磷酸化位点及糖基化位点;运用SOMPA、SWISS-MODEL软件分别预测蛋白的二级和三级结构;运用DoGSiteScorer软件预测蛋白的小分子结合口袋;运用STRING数据库分析MazF5互作蛋白;运用BioEdit软件分析氨基酸序列同源性;运用ABCpred和SYFPEITHI对蛋白的B、Th、CTL细胞抗原表位进行预测。结果 MazF5蛋白分子式为C_(510)H_(866)N_(158)O_(149)S_7,所含原子数为1 690,由109个氨基酸组成。预测的等电点PI为9.00,半衰期为30 h,脂溶性指数是113.58,不稳定指数为51.82,为不稳定蛋白。此外,MazF5蛋白无信号肽、为非跨膜蛋白、拥有多个磷酸化及糖基化位点,二级结构中无规则卷曲含量最多。同时,它含有多个小分子结合区域,并能与MazE5、MazF3、MazF6、MazF9等多个蛋白相互作用。氨基酸序列同源性分析结果显示结核分枝杆菌与卡内特分枝杆菌同源性较高。MazF5蛋白还具有多个B、T细胞优势抗原表位。结论 MazF5蛋白存在多个位点和抗原表位,存在蛋白相互作用网络,具有多个小分子结合位点,是潜在的结核病检测血清标志物。

Objective Probing the structure and function of Mycobacterium tuberculosis MazF5 protein. Methods Sequences encoding MazF5 gene information and amino acids were obtained from the NCBI database;the physicochemical properties of the protein was analyzed using the ProtParam application plug-in of Expasy;ProtScale, SignalP 4.1,TMHMM Serverv.2.0,NetPhos 3.1,and YinOYang 1.2 software were used to predict the hydrophilicity, signal peptide, transmembrane region, phosphorylation site, and glycosylation site of the protein, respectively;SOMPA and SWISS-MODEL software were used to predict the secondary and tertiary structures of the protein, respectively;the small molecule binding pockets of the protein were predicted using DoGSiteScorer software;the STRING database was used to analyze the MazF5-interacting proteins;the amino acid sequence homology was analysed using BioEdit software;B,Th and CTL cellular antigenic epitopes of the protein were predicted using ABCpred and SYFPEITHI. Results MazF5 protein has a molecular formula of C_(510)H_(866)N_(158)O_(149)S_7,contains 1 690 atoms and consists of 109 amino acids. The predicted isoelectric point PI was 9.00,the half-life was 30 h, the lipid solubility index was 113.58,and the instability index was 51.82,suggesting an unstable protein. In addition, the MazF5 protein has no signal peptide, is a non-transmembrane protein, possesses multiple phosphorylation and glycosylation sites, and has the highest amount of irregular curls in its secondary structure.At the same time, it contains several small molecule binding regions and interacts with several proteins including MazE5,MazF3,MazF6,MazF9 and others. Amino acid sequence homology analysis shows high homology between M. tuberculosis and M. canettii. MazF5 protein also has multiple B and T cell dominant antigenic epitopes. Conclusion The presence of multiple sites and antigenic epitopes, a network of protein interactions, and multiple small molecule binding sites make the MazF5 protein a potential serum marker for tuberculosis detection.