结核分枝杆菌休眠相关蛋白Tgs3的生物信息学分析

Bioinformatics analysis of Tgs3protein of Mycobacterium tuberculosis

目的 预测结核分枝杆菌休眠相关蛋白二酰基甘油O-酰基转移酶3(diacyglycerol O-acyltransferase 3,Tgs3)的结构与功能,以期为潜伏结核的治疗及预防提供研究思路。方法 从NCBI网站获取Rv3234c基因及其编码Tgs3蛋白的基本信息;运用ProtParam与ProtScale分析Tgs3蛋白的理化性质和亲疏水性;使用SignaIP-4.1、TMHMM、PSORT进行蛋白信号肽、跨膜结构域及亚细胞定位分析;采用NetPhosBac-1.0、NetOGlyc-4.0 Server预测Tgs3蛋白的磷酸化位点与糖基化位点;使用SOPMA预测Tgs3蛋白的二级结构,运用SWISS-MODEL、I-TASSE进行三级结构建模及分析;利用MEGA、Clustal Omega软件进行氨基酸序列分析;利用STRING、David数据库分析蛋白相互作用网络;使用IEDB网站预测Tgs3蛋白的B、Th细胞及CTL细胞抗原表位。结果 Tgs3蛋白由271个氨基酸组成,分子质量为30.378 83 ku,理论pI值9.83,分子式为C1345H2176N402O390S5,为亲水性蛋白;该蛋白不含信号肽,为非分泌蛋白,定位于细胞质;Tgs3具有多个磷酸化与糖基化位点;二级结构主要由α螺旋(43.17%)、无规卷曲(38.75%)组成,三级结构分析显示Q138-N142-G14、F12-M22-Q138为Tgs3蛋白的配体结合位点;Tgs3蛋白与Rv1425氨基酸序列相似性较高,与DGAT1、DGAT2相似性较低;Tgs3含有多个优势B细胞及T细胞抗原表位。结论 生物信息学预测Tgs3蛋白为胞浆蛋白,含有多个磷酸化与糖基化位点,其氨基酸序列与人体二酰甘油酰基转移酶氨基酸序列相似性较低,含有多个B、T细胞抗原表位,为潜伏结核药物及疫苗靶点的研发提供了方向。

Objective To predict the structure and function of diacyglycerol O-acyltransferase 3(Tgs3),a dormancy-associated protein of Mycobacterium tuberculosis,with a view to providing ideas for the treatment and prevention of latent tuberculosis.Methods The NCBI website was used to obtain the basic information of Rv3234cgene and its encoded Tgs3protein;ProtParam and ProtScale were used to analyze the physicochemical properties and hydrophobicity of Tgs3 protein;SignaIP-4.1,TMHMM,PSORT to analyze the protein signal peptide,transmembrane structural domain and sub-cellular localization;phosphorylation sites and glycosylation sites of Tgs3protein were predicted by NetPhosBac-1.0,and NetOGlyc-4.0Server;SOPMA was used to predict the secondary structure of Tgs3protein,SWISS-MODEL,I-TASSE for tertiary structure modeling and subsequent analysis;MEGA and Clustal Omega software were used for amino acid se-quence analysis;STRING and David database were used for protein interaction network analysis;IEDB website was used to predict the antigenic epitopes of Tgs3protein in B cells,Th cells and CTL cells.Results Tgs3protein consisted of 271amino acids,with a relative molecular weight of 30,378.83,pI value of 9.83,and a molecular formula of C 1345 H 2176 N 402 O 390 S 5,and was a hydrophilic protein;no signal peptide,non-secretory protein,localized in cytoplasm;it had multiple phos-phorylation and glycosylation sites;the secondary structure mainly consisted ofα-helix(43.17%)and random coiling(38.75%),and the tertiary structure analysis showed that Q138-N142-G14and F12-M22-Q138were the ligand binding sites of Tgs3protein;Tgs3protein had high amino acid sequence similarity with Rv1425,and low similarity with DGAT1and DGAT2;it contained several dominant B-cell and T-cell antigenic epitopes.Conclusion The bioinformatics method pre-dicted that the Tgs3protein was a cytoplasmic protein containing multiple phosphorylation and glycosylation sites,and had low amino acid sequence similarity to human diacylglycerol acyltransferase,and contained multiple B and T cell antigenic epitopes,which provided a direction for the development of latent tuberculosis drug and vaccine targets.