Structural highlights
Function[SIGW_BACSU] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. Extracytoplasmic function (ECF) sigma factors are held in an inactive form by a cognate anti-sigma factor (RsiW for this protein) until released by regulated membrane proteolysis. Sigma-W controls genes involved in transport processes and detoxification.[1] [2] Publication Abstract from PubMedSigma factors are key proteins that mediate the recruitment of RNA polymerase to the promoter regions of genes, for the initiation of bacterial transcription. Multiple sigma factors in a bacterium selectively recognize their cognate promoter sequences, thereby inducing the expression of their own regulons. In this paper, we report the crystal structure of the sigma4 domain of Bacillus subtilis SigW bound to the -35 promoter element. Purine-specific hydrogen bonds of the -35 promoter element with the recognition helix alpha9 of the sigma4 domain occurs at three nucleotides of the consensus sequence (G-35, A-34, and G'-31 in G-35A-34A-33A-32C-31C-30T-29). The hydrogen bonds of the backbone with the alpha7 and alpha8 of the sigma4 domain occurs at G'-30. These results elucidate the structural basis of the selective recognition of the promoter by SigW. In addition, comparison of SigW structures complexed with the -35 promoter element or with anti-sigma RsiW reveals that DNA recognition and anti-sigma factor binding of SigW are mutually exclusive. Structural analysis of the recognition of the -35 promoter element by SigW from Bacillus subtilis.,Kwon E, Devkota SR, Pathak D, Dahal P, Kim DY PLoS One. 2019 Aug 28;14(8):e0221666. doi: 10.1371/journal.pone.0221666., eCollection 2019. PMID:31461489[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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