4NQW

Structure of Mycobacterium tuberculosis extracytoplasmic function sigma factor SigK in complex with the cytosolic domain of its cognate anti-sigma factor RskA

Replaces:  3VDO

Summary for 4NQW

• Entry DOI: 10.2210/pdb4nqw/pdb
• Descriptor: ECF RNA polymerase sigma factor SigK, Anti-sigma-K factor RskA, CADMIUM ION, ... (4 entities in total)
• Functional Keywords: sigma factor, transcription initiation, dna binding, promoter dna binding and transcription initiation, anti-sigma factor, dna binding protein-protein binding complex, dna binding protein/protein binding
• Biological source: Mycobacterium tuberculosis; More
• Cellular location: Cell membrane; Single-pass membrane protein (Potential): O53729
• Total number of polymer chains: 2
• Total formula weight: 32651.35

Authors

Shukla, J.K.,Gopal, B. (deposition date: 2013-11-25, release date: 2014-01-22, Last modification date: 2024-11-20)

Primary citation

Shukla, J.,Gupta, R.,Thakur, K.G.,Gokhale, R.,Gopal, B.
Structural basis for the redox sensitivity of the Mycobacterium tuberculosis SigK-RskA sigma-anti-sigma complex
Acta Crystallogr.,Sect.D, 70:1026-1036, 2014

PubMed 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) 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.

PubMed: 24699647
DOI: 10.1107/S1399004714000121

Experimental method

X-RAY DIFFRACTION (2.4 Å)