DosT and DevS are oxygen-switched kinases in Mycobacterium tuberculosis

Eduardo Henrique Silva Sousa, Jason Robert Tuckerman, Gonzalo Gonzalez, Marie Alda Gilles-Gonzalez

Research output: Contribution to journalArticle

101 Scopus citations

Abstract

Exposure of Mycobacterium tuberculosis to hypoxia is known to alter the expression of many genes, including ones thought to be involved in latency, via the transcription factor DevR (also called DosR). Two sensory kinases, DosT and DevS (also called DosS), control the activity of DevR. We show that, like DevS, DosT contains a heme cofactor within an N-terminal GAF domain. For full-length DosT and DevS, we determined the ligand-binding parameters and the rates of ATP reaction with the liganded and unliganded states. In both proteins, the heme state was coupled to the kinase such that the unliganded, CO-bound, and NO-bound forms were active, but the O2-bound form was inactive. Oxygen-bound DosT was unusually inert to oxidation to the ferric state (half life in air >60 h). Though the kinase activity of DosT was unaffected by NO, this ligand bound 5000 times more avidly than O2 to DosT (Kd [NO] ∼5 nM versus Kd [O2] = 26 μM). These results demonstrate direct and specific O2 sensing by proteins in M. tuberculosis and identify for the first time a signal ligand for a sensory kinase from this organism. They also explain why exposure of M. tuberculosis to NO donors under aerobic conditions can give results identical to hypoxia, i.e., NO saturates DosT, preventing O2 binding and yielding an active kinase. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish (US)
Pages (from-to)1708-1719
Number of pages12
JournalProtein Science
Volume16
Issue number8
DOIs
StatePublished - Aug 1 2007

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Keywords

  • FixL
  • GAF domain
  • Heme-based sensor
  • Histidine-protein kinase
  • Host-microbe interactions
  • Oxygen sensor
  • Response regulator
  • Sensor kinase
  • Signal transduction

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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