@article{open1532,
          volume = {70},
          number = {Pt 4},
           month = {April},
          author = {Jinal Shukla and Radhika Gupta and Krishan Gopal Thakur and Rajesh Gokhale and B Gopal},
           title = {Structural basis for the redox sensitivity of the Mycobacterium tuberculosis SigK-RskA {\ensuremath{\sigma}}-anti-{\ensuremath{\sigma}} complex.},
       publisher = {Malden, MA : Wiley-Blackwell},
            year = {2014},
         journal = {Acta crystallographica. Section D, Biological crystallography},
           pages = {1026--36},
        keywords = {transcription; redox sensitivity; secreted antigens; extracytoplasmic function [sigma] factors.},
             url = {http://crdd.osdd.net/open/1532/},
        abstract = {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) {\ensuremath{\sigma}} factor {\ensuremath{\sigma}}(K) governs the transcription of the serodominant antigens MPT70 and MPT83. The cellular levels of {\ensuremath{\sigma}}(K) are regulated by the membrane-associated anti-{\ensuremath{\sigma}}(K) (RskA) that localizes {\ensuremath{\sigma}}(K) in an inactive complex. The crystal structure of M. tuberculosis {\ensuremath{\sigma}}(K) in complex with the cytosolic domain of RskA (RskAcyto) revealed a disulfide bridge in the -35 promoter-interaction region of {\ensuremath{\sigma}}(K). Biochemical experiments reveal that the redox potential of the disulfide-forming cysteines in {\ensuremath{\sigma}}(K) is consistent with its role as a sensor. The disulfide bond in {\ensuremath{\sigma}}(K) influences the stability of the {\ensuremath{\sigma}}(K)-RskAcyto complex but does not interfere with {\ensuremath{\sigma}}(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.}
}