Project description:UnlabelledThe Mycobacterium tuberculosis Proteome Comparison Database (MTB-PCDB) is an online database providing integrated access to proteome sequence comparison data for five strains of Mycobacterium tuberculosis (H37Rv, H37Ra, CDC 1551, F11 and KZN 1435) sequenced completely so far. MTB-PCDB currently hosts 40252 protein sequence comparison data obtained through inter-strain proteome comparison of five different strains of MTB. 2373 proteins were found to be identical in all 5 strains using MTB H(37)Rv as reference strain. To enable wide use of this data, MTB-PCDB provides a set of tools for searching, browsing, analyzing and downloading the data. By bringing together, M. tuberculosis proteome comparison among virulent & avirulent strains and also drug susceptible & drug resistance strains MTB-PCDB provides a unique discovery platform for comparative proteomics among these strains which may give insights into the discovery & development of TB drugs, vaccines and biomarkers.AvailabilityThe database is available for free at http://www.bicjbtdrc-mgims.in/MTB-PCDB/
Project description:Enzymes of the de novo purine biosynthetic pathway have been identified as essential for the growth and survival of Mycobacterium tuberculosis and thus have potential for the development of anti-tuberculosis drugs. The final two steps of this pathway are carried out by the bifunctional enzyme 5-aminoimidazole-4-carboxamide ribonucleotide transformylase/inosine monophosphate cyclohydrolase (ATIC), also known as PurH. This enzyme has already been the target of anti-cancer drug development. We have determined the crystal structures of the M. tuberculosis ATIC (Rv0957) both with and without the substrate 5-aminoimidazole-4-carboxamide ribonucleotide, at resolutions of 2.5 and 2.2 Å, respectively. As for other ATIC enzymes, the protein is folded into two domains, the N-terminal domain (residues 1-212) containing the cyclohydrolase active site and the C-terminal domain (residues 222-523) containing the formyltransferase active site. An adventitiously bound nucleotide was found in the cyclohydrolase active site in both structures and was identified by NMR and mass spectral analysis as a novel 5-formyl derivative of an earlier intermediate in the biosynthetic pathway 4-carboxy-5-aminoimidazole ribonucleotide. This result and other studies suggest that this novel nucleotide is a cyclohydrolase inhibitor. The dimer formed by M. tuberculosis ATIC is different from those seen for human and avian ATICs, but it has a similar ∼50-Å separation of the two active sites of the bifunctional enzyme. Evidence in M. tuberculosis ATIC for reactivity of half-the-sites in the cyclohydrolase domains can be attributed to ligand-induced movements that propagate across the dimer interface and may be a common feature of ATIC enzymes.
Project description:This study evaluated the performance of cobas MTB and cobas MTB-RIF/INH for the diagnosis of tuberculosis and detection of rifampicin (RIF) and isoniazid (INH) resistance. Adults presenting with pulmonary tuberculosis symptoms were recruited in South Africa, Moldova, and India. Performance of cobas MTB was assessed against culture, whereas cobas MTB-RIF/INH was assessed using phenotypic drug susceptibility testing and whole-genome sequencing as composite reference standards. Xpert MTB/RIF (Xpert) or Xpert MTB/RIF Ultra (Ultra) was used as a comparator. The overall sensitivity and specificity of cobas MTB were 95% (95% CI, 93%-96%) and 96% (95% CI, 95%-97%). Among smear-negatives, the sensitivity of cobas MTB was 75% (95% CI, 66%-83%). Among participants tested with both cobas MTB and Xpert, sensitivity was 96% (95% CI, 94%-97%) for cobas MTB and 95% (95% CI, 93%-97%) for Xpert. Among participants tested with both cobas MTB and Ultra, sensitivity was 88% (95% CI, 81%-92%) for cobas MTB and 89% (95% CI, 83%-93%) for Ultra. Sensitivity and specificity of cobas MTB-RIF/INH for RIF and INH detection were 90% (95% CI, 84%-94%) and 100% (95% CI, 99%-100%), and 89% (95% CI, 84%-93%) and 99.5% (95% CI, 98%-100%), respectively. The cobas MTB and cobas MTB-RIF/INH assays exhibited high performance in a diverse population and present a suitable option for molecular detection of tuberculosis and RIF and INH resistance.