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Open Access Highly Accessed Research article

Comparison of membrane proteins of Mycobacterium tuberculosis H37Rv and H37Ra strains

Hiwa Målen12, Gustavo A De Souza13, Sharad Pathak12, Tina Søfteland1 and Harald G Wiker12*

Author Affiliations

1 Section for Microbiology and Immunology, the Gade Institute, University of Bergen, Bergen, Norway

2 Department of Microbiology and Immunology, Haukeland University Hospital, Bergen, Norway

3 Proteomic Unit, Department of Biomedicine, University of Bergen, Norway

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BMC Microbiology 2011, 11:18  doi:10.1186/1471-2180-11-18

Published: 24 January 2011

Abstract

Background

The 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.

Results

We 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.

Conclusion

Our 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.