Structural basis for the redox sensitivity of the Mycobacterium tuberculosis SigK-RskA σ-anti-σ complex.

J. Shukla, R. Gupta, K. Thakur, R. Gokhale, B. Gopal
Acta crystallographica. Section D, Biological crystallography. 2014 70:0 PubMed: 24699647

Abstract: {"AbstractText"=>"The host-pathogen interactions in Mycobacterium tuberculosis infection are significantly influenced by redox stimuli and alterations in the levels of secreted antigens. The extracytoplasmic function (ECF) σ factor σ(K) governs the transcription of the serodominant antigens MPT70 and MPT83. The cellular levels of σ(K) are regulated by the membrane-associated anti-σ(K) (RskA) that localizes σ(K) in an inactive complex. The crystal structure of M. tuberculosis σ(K) in complex with the cytosolic domain of RskA (RskAcyto) revealed a disulfide bridge in the -35 promoter-interaction region of σ(K). Biochemical experiments reveal that the redox potential of the disulfide-forming cysteines in σ(K) is consistent with its role as a sensor. The disulfide bond in σ(K) influences the stability of the σ(K)-RskAcyto complex but does not interfere with σ(K)-promoter DNA interactions. It is noted that these disulfide-forming cysteines are conserved across homologues, suggesting that this could be a general mechanism for redox-sensitive transcription regulation."}

Described groups:

  • ECF57
  • ECF19
  • ECF18
  • ECF288

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