Structural highlights
Publication Abstract from PubMedGene expression in bacteria is regulated at the level of transcription initiation, a process driven by sigma factors. The regulation of sigma factor activity proceeds from the regulation of their cytoplasmic availability, which relies on specific inhibitory proteins called anti-sigma factors. With anti-sigma factors regulating their availability according to diverse cues, extracytoplasmic function sigma factors (sigmaECF) form a major signal transduction system in bacteria. Here, structure:function relationships have been characterized in an emerging class of minimal-size transmembrane anti-sigma factors, using CnrY from Cupriavidus metallidurans CH34 as a model. This study reports the 1.75-A-resolution structure of CnrY cytosolic domain in complex with CnrH, its cognate sigmaECF, and identifies a small hydrophobic knob in CnrY as the major determinant of this interaction in vivo. Unsuspected structural similarity with the molecular switch regulating the general stress response in alpha-proteobacteria unravels a new class of anti-sigma factors targeting sigmaECF. Members of this class carry out their function via a 30-residue stretch that displays helical propensity but no canonical structure on its own. The Crystal Structure of the Anti-sigma Factor CnrY in Complex with the sigma Factor CnrH Shows a New Structural Class of Anti-sigma Factors Targeting Extracytoplasmic Function sigma Factors.,Maillard AP, Girard E, Ziani W, Petit-Hartlein I, Kahn R, Coves J J Mol Biol. 2014 Apr 12. pii: S0022-2836(14)00177-6. doi:, 10.1016/j.jmb.2014.04.003. PMID:24727125[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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