Comparison Of Proteomes Of Avirulent Mycobacterium Tuberculosis H37Ra And Virulent Mycobacterium Tuberculosis H37Rv
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Date
2011-09
Authors
Ang, Kai Cheen
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Journal ISSN
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Publisher
Universiti Sains Malaysia
Abstract
M. tuberculosis H37Ra, which was discovered in 1935, was derived from the virulent strain H37. In order to identify the factors that are correlated to virulence in M. tuberculosis H37Rv, 2D-gel profile of three virulent strains at culture grown for three time points (14, 28 and 50 days) were compared with its avirulent counterpart M. tuberculosis H37Ra. A total of 250 protein spots were visualized by Coomassie blue staining. The protein profiles of the M. tuberculosis H37Rv and M. tuberculosis H37Ra were highly similar (R2~0.70), thirty one spots were found to be differentially expressed at 14, 28 and 50 days cultures, whereby 14 spots were identified from Tris extract and 17 spots were identified from TLB extract. Twenty-six spots could be identified by LCMS/MS and showed to consist of 32 proteins. L-guluno-1,4-lactone dehydrogenase (Rv1771) was significantly up-regulated in 14-day culture of M. tuberculosis H37Rv only. Three proteins showed differential expression in 28-day culture only. These proteins include the conserved hypothetical protein Acg (acg, Rv2032), macrolide-transport ATP-binding cassette protein (ABC transporter, Rv2477c) and fatty-acid-CoA ligase (fadD28, Rv2941). Acg which is involved in dormancy regulon was down-regulated in M. tuberculosis H37Rv. Rv2477c and fadD28 were up-regulated in M. tuberculosis H37Rv. M. tuberculosis is usually resistant to common antibiotics; this may be due to the presence of several ABC transporters on the cell membrane that could transport the antibiotics out from cells. Down-regulation of fadD28, which is involved in cell wall biosynthesis, may explain the low survival of M. tuberculosis H37Ra intracellularly. This work has provided the information on the proteome of M. tuberculosis H37Rv and M. tuberculosis H37Ra, the differential protein expression between the two strains may give a better understanding on phenotypic and pathogenesis
between M. tuberculosis H37Rv and its avirulent counterpart M. tuberculosis H37Ra. Further investigation on the reported proteins may also lead to identification of candidate biomarkers for diagnosis and treatment of the disease.
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Keywords
The proteome of M. tuberculosis H37Rv , and M. tuberculosis H37Ra