<p>This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.</p> <p>The plasma <italic>membrane of Mycobacterium tuberculosis</italic> is likely to contain proteins that could serve as novel drug targets, diagnostic probes or even components of a vaccine
against tuberculosis. With this in mind, we have undertaken proteome analysis of the
membrane of <italic>M. tuberculosis</italic> H37Rv. Isolated membrane vesicles were extracted with
either a detergent (Triton X114) or an alkaline buffer (carbonate) following two of the
protocols recommended for membrane protein enrichment. Proteins were resolved
by 2D-GE using immobilized pH gradient (IPG) strips, and identified by peptide
mass mapping utilizing the <italic>M. tuberculosis</italic> genome database. The two extraction
procedures yielded patterns with minimal overlap. Only two proteins, both HSPs,
showed a common presence. MALDI–MS analysis of 61 spots led to the identification
of 32 proteins, 17 of which were new to the <italic>M. tuberculosis</italic> proteome database.
We classified 19 of the identified proteins as ‘membrane-associated’; 14 of these
were further classified as ‘membrane-bound’, three of which were lipoproteins. The
remaining proteins included four heat-shock proteins and several enzymes involved
in energy or lipid metabolism. Extraction with Triton X114 was found to be more
effective than carbonate for detecting ‘putative’ <italic>M. tuberculosis</italic> membrane proteins.
The protocol was also found to be suitable for comparing BCG and <italic>M. tuberculosis</italic>
membranes, identifying ESAT-6 as being expressed selectively in <italic>M. tuberculosis</italic>.
While this study demonstrates for the first time some of the membrane proteins of
<italic>M. tuberculosis</italic>, it also underscores the problems associated with proteomic analysis
of a complex membrane such as that of a mycobacterium.</p>
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Comp Funct Genomics. 2002 Dec; 3(6):470-483