Characterization of the <i>Mycobacterium tuberculosis</i> Proteome by Liquid Chromatography Mass Spectrometry-based Proteomics Techniques: A Comprehensive Resource for Tuberculosis Research

Approximately, one-third of the world’s population is infected with Mycobacterium tuberculosis, the causative agent of Tuberculosis. Secreted and membrane proteins that interact with the host play important roles for the pathogenicity of the bacteria and are potential drug targets or components of vaccines. In this present study, subcellular fractionation in combination with membrane enrichment was used to comprehensively analyze the M. tuberculosis proteome. The proteome of the M. tuberculosis cell wall, membrane, cytosol, lysate, and culture filtrate was defined with a high coverage. Exceptional enrichment for membrane proteins was achieved using wheat germ agglutinin (WGA)-affinity two-phase partitioning, a technique that has to date not yet been exploited for the enrichment of mycobacterial membranes. Overall, 1051 M. tuberculosis protein groups including 183 transmembrane proteins have been identified by LC–MS/MS analysis using stringent database search criteria with a minimum of two peptides and an estimated FDR of less than 1%. With many mycobacterial antigens and lipoglycoproteins identified, the results from this study suggest that many of the newly discovered proteins could represent potential candidates mediating host–pathogen interactions. In addition, this data set provides experimental information about protein localization and thus serves as a valuable resource for M. tuberculosis proteome research.全球约三分之一的人口感染了结核分枝杆菌（Mycobacterium tuberculosis）——结核病的致病菌。与宿主相互作用的分泌蛋白及膜蛋白，在细菌致病过程中发挥关键作用，同时也是潜在的药物靶点或疫苗候选组分。本研究采用亚细胞分级分离结合膜富集的策略，对结核分枝杆菌的蛋白质组进行了全面解析，实现了对结核分枝杆菌细胞壁、膜、细胞质、裂解液及培养滤液蛋白质组的高覆盖度鉴定。本研究采用麦胚凝集素（WGA）亲和两相分配法实现了膜蛋白的高效富集——该技术此前尚未被应用于分枝杆菌膜的富集工作中。整体而言，本研究通过液相色谱-串联质谱（LC–MS/MS）分析，并采用严格的数据库搜索标准（至少匹配2条肽段，估计错误发现率（FDR）低于1%），共鉴定到1051个结核分枝杆菌蛋白质群组，其中包含183个跨膜蛋白。本研究鉴定到多种分枝杆菌抗原及脂糖蛋白，研究结果提示，诸多新发现的蛋白质可能是介导宿主-病原体相互作用的潜在候选分子。此外，本数据集提供了蛋白质定位的实验数据，可为结核分枝杆菌蛋白质组研究提供宝贵的参考资源。