Characterization of the Mycobacterium tuberculosis 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.