TAILIEUCHUNG - Báo cáo khoa học: Loss of kinase activity in Mycobacterium tuberculosis multidomain protein Rv1364c

The alternative sigma factors are regulated by a phosphorylation-mediated signal transduction cascade involving anti-sigma factors and anti-anti-sigma factors. The proteins regulating Mycobacterium tuberculosissigma factor F (SigF), anti-SigF and anti-anti-SigF have been identified, but the factors catalyzing phosphorylation–dephosphorylation have not been well estab-lished. | ỊFEBS Journal Loss of kinase activity in Mycobacterium tuberculosis multidomain protein Rv1364c Preeti Sachdeva1 2 Azeet Narayan1 Richa Misra1 Vani Brahmachari2 and Yogendra Singh1 1 Institute of Genomics and Integrative Biology CSIR Delhi India 2 Dr B. R. Ambedkar Center for BiomedicalResearch University of Delhi India Keywords kinase Mycobacterium RsbW Rv1364c SigF Correspondence Y. Singh Institute of Genomics and Integrative Biology MallRoad Delhi 110007 India Fax 11 2766 7471 Tel 11 2766 6156 E-mail ysingh@ Received 7 September 2008 revised 16 October 2008 accepted 22 October 2008 doi The alternative sigma factors are regulated by a phosphorylation-mediated signal transduction cascade involving anti-sigma factors and anti-anti-sigma factors. The proteins regulating Mycobacterium tuberculosis sigma factor F SigF anti-SigF and anti-anti-SigF have been identified but the factors catalyzing phosphorylation-dephosphorylation have not been well established. We identified a distinct pathogenic species-specific multidomain protein Rv1364c in which the components of the entire signal transduction cascade for SigF regulation appear to be encoded in a single polypeptide. Sequence analysis of M. tuberculosis Rv1364c resulted in the prediction of various domains namely a phosphatase RsbU domain an anti-SigF RsbW domain and an anti-anti-SigF RsbV domain. We report that the RsbU domain of Rv1364c bears all the conserved features of the PP2C-type serine threonine phosphatase family whereas its RsbW domain has certain substitutions and deletions in regions important for ATP binding. Another anti-SigF protein in M. tuberculosis UsfX Rv3287c shows even more unfavorable substitutions in the kinase domain. Biochemical assay with the purified RsbW domain of Rv1364c and UsfX showed the loss of ability of autophosphorylation and phosphotransfer to cognate anti-anti-SigF proteins or artificial substrates. Both the Rv1364c RsbW domain and UsfX

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