Comparison of membrane proteins of Mycobacterium tuberculosisH37Rv and H37Ra strains

Abstract

BackgroundThe potential causes for variation in virulence between distinct M. tuberculosis strains are still not fully known. However, differences in protein expression are probably an important factor. In this study we used a label-free quantitative proteomic approach to estimate differences in protein abundance between two closely related M. tuberculosis strains; the virulent H37Rv strain and its attenuated counterpart H37Ra.ResultsWe were able to identify more than 1700 proteins from both strains. As expected, the majority of the identified proteins had similar relative abundance in the two strains. However, 29 membrane-associated proteins were observed with a 5 or more fold difference in their relative abundance in one strain compared to the other. Of note, 19 membrane- and lipo-proteins had higher abundance in H37Rv, while another 10 proteins had a higher abundance in H37Ra. Interestingly, the possible protein-export membrane protein SecF (Rv2586c), and three ABC-transporter proteins (Rv0933, Rv1273c and Rv1819c) were among the more abundant proteins in M. tuberculosis H37Rv.ConclusionOur data suggests that the bacterial secretion system and the transmembrane transport system may be important determinants of the ability of distinct M. tuberculosis strains to cause disease.

Differential Detergent Extraction of Mycobacterium marinum Cell Envelope Proteins Identifies an Extensively Modified Threonine-Rich Outer Membrane Protein with Channel Activity

“…These results indicate that the classical model of outer membrane proteins as (predominantly) being ␤-barrels might not apply to all mycolate outer membrane proteins. Recently, various attempts were made to define proteins in the cell envelope or cell wall fractions of different strains of M. tuberculosis, M. bovis BCG, and Mycobacterium avium (20)(21)(22), but none were dedicated to the specific identification of MOMPs. In this study, we developed a method to specifically enrich for MOM proteins by differential detergent extraction of mycobacterial cell envelopes.…”

Comparative study of Mycobacterium tuberculosis and Mycobacterium bovis protein profiles

“…Malen et al [17] compared membrane proteins of M. tuberculosis H37Rv and H37Ra strains and examined the properties of more than 1700 proteins of both strains. Almost all identified proteins were too much similar, although strains were different in 5 or more proteins in 29 membrane or membrane associated proteins.…”

Proteomic progress in studying tuberculosis from 2010 to 2011

“…The results showed that 29 membrane-associated proteins with a 5 or more fold difference in their relative abundance in one strain compared to the other. Of which, 19 membrane-and lipo-proteins such as three ABC transporter proteins (Rv0933, Rv1273c and Rv1819c) had higher abundance in H37Rv, while another 10 proteins had a higher abundance in H37Ra [7]. Furthermore, Mehaffy et al [11] studied the proteomes of secreted and cytosolic proteins of genetically closely related strains of M. tuberculosis through 2DE and iTRAQ-LC-MS methods, and found that some enzymes such as GltA2, SucC, Gnd1 and Eno were expressed differently in different strains.…”

“…During the last two years, a label-free proteomic method based on 1DE separation, LC-MS identification, followed by emPAI quantification was reported to identify differentially abundant proteins in closely related hypo-and hyper-virulent clinical Mycobacterium tuberculosis Beijing isolates [14]. Another label-free proteomics based on SDS-PAGE separation followed by MaxQuant peak intensity calculations was developed to analyze membrane proteins of Mycobacterium tuberculosis H37Rv and H37Ra strains [7].…”

“…Although proteomics has lagged behind genomics and transcriptomics due to instrumental and sensitivity problems, the application of proteomics to the study of infectious agents is beginning to emerge. Such applications include searching potential biomarkers for diagnosis [6], identifying complete virulence factor inventories [7], studying the response of both host and pathogen to the infection process (reviewed by Bhavsar AP [8] and Boshoff HI [9]), and elucidating mechanistic actions of virulence factors as they interface with host cells [10]. In this study, we reviewed proteomic progresses in TB studies from 2010 to 2011 as shown in Figure 1.…”