Comprehensive proteomic profiling of clinically relevant strains of Mycobacterium tuberculosis

Includes bibliographical references.Tuberculosis is an airborne infectious disease caused by the bacillus known as Mycobacterium tuberculosis. Despite limited genetic variability, Mycobacterium tuberculosis strains exhibit vast discrepancies in phenotypic presentation in terms of virulence, elicited immune response and transmissibility. This study aims to use Mass Spectrometry (MS) tools to quantitatively and qualitatively investigate the total proteome expressed by various epidemiologically significant strains within the Mycobacterium tuberculosis complex (MTBC) as well as a clinically relevant non-tuberculous Mycobacteria (NTM) strain when cultured in vitro. We aim to use the experimental data obtained using discovery mass spectrometry to identify candidate proteins to use in the design of multiple reaction monitoring (MRM) MS experiments for targeted biomarker validation in patient derived biological samples such as sputum. Liquid chromatography mass spectrometry (LC MS/MS) and data capture were carried out using the LTQ Orbitrap Velos. 1D LC was carried out on gel fractionated samples to increase proteome coverage. This allowed a significant increase in the number of protein identifications of up to 80% proteome coverage per strain. Comparative analysis of the datasets was carried out to identify and define the core-proteome expressed across all strains as well as to identify differentially expressed proteins amongst the strains