Cross talk between DevS sensor kinase homologue, Rv2027c, and DevR response regulator of Mycobacterium tuberculosis.
Rv2027c is a putative orphan histidine sensor kinase that bears strong homology to DevS of the hypoxia-responsive DevR-DevS two-component system in M. tuberculosis. The cytosolic C-terminal domain of Rv2027c protein (Rv2027c(194)) was overexpressed in E. coli and biochemically characterized. Rv2027c(194) underwent autophosphorylation at a conserved His(392) residue and engaged in phosphotransfer with DevR response regulator. The rates of autophosphorylation and the stabilities of the phosphorylated species were broadly similar in Rv2027c and DevS. However, unlike DevS, Rv2027c utilized Ca(2+) as an alternative divalent ion during autophosphorylation. In contrast to DevS which completed phosphotransfer to DevR in 5-10 min, phosphotransfer from Rv2027c approximately P was only partial at 30 min. Unlike devS transcription that was hypoxia-responsive, Rv2027c transcript levels were not upregulated from basal levels during hypoxia. The differential regulation of devS and Rv2027c genes, the ability of Rv2027c to utilize Ca(2+) as a divalent cation in autophosphorylation at physiological concentrations and to engage in phosphotransfer with DevR suggests that the DevR regulon could be modulated by more than one environmental cue relayed through DevS and Rv2027c.
Saini
Deepak Kumar
DK
Department of Biotechnology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India.
Malhotra
Vandana
V
Tyagi
Jaya Sivaswami
JS
D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D002412:Cations; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000378:metabolism; D016680:Genome, Bacterial; D049452:Green Fluorescent Proteins; D006639:Histidine / Q000737:chemistry; D000071677:Histidine Kinase; D000860:Hypoxia; D007477:Ions; D008164:Luminescent Proteins / Q000378:metabolism; D008957:Models, Genetic; D016297:Mutagenesis, Site-Directed; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D010766:Phosphorylation; D010770:Phosphotransferases / Q000737:chemistry* / Q000378:metabolism; D017354:Point Mutation; D011485:Protein Binding; D011487:Protein Conformation; D011494:Protein Kinases / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012984:Software; D013997:Time Factors; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism; D015854:Up-Regulation
D001426:Bacterial Proteins; D002412:Cations; C098956:DevR protein, Nostoc; D007477:Ions; D008164:Luminescent Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins; D006639:Histidine; D010770:Phosphotransferases; D011494:Protein Kinases; D000071677:Histidine Kinase; D002118:Calcium