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== Function == | == Function == | ||
[[http://www.uniprot.org/uniprot/RSGI1_CLOTH RSGI1_CLOTH]] Anti-sigma factor for SigI1. Negatively regulates SigI1 activity through direct interaction (PubMed:20937888). Binding of the polysaccharide substrate to the extracellular C-terminal sensing domain of RsgI1 may induce a conformational change in its N-terminal cytoplasmic region, leading to the release and activation of SigI1 (Probable).<ref>PMID:20937888</ref> <ref>PMID:20937888</ref> [[http://www.uniprot.org/uniprot/SIGI1_CLOTH SIGI1_CLOTH]] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released (By similarity). This sigma factor is involved in regulation of cellulosomal genes via an external polysaccharide-sensing mechanism. SigI1 promotes transcription from sigI1 and celS promoters (PubMed:20937888).[HAMAP-Rule:MF_02064]<ref>PMID:20937888</ref> | [[http://www.uniprot.org/uniprot/RSGI1_CLOTH RSGI1_CLOTH]] Anti-sigma factor for SigI1. Negatively regulates SigI1 activity through direct interaction (PubMed:20937888). Binding of the polysaccharide substrate to the extracellular C-terminal sensing domain of RsgI1 may induce a conformational change in its N-terminal cytoplasmic region, leading to the release and activation of SigI1 (Probable).<ref>PMID:20937888</ref> <ref>PMID:20937888</ref> [[http://www.uniprot.org/uniprot/SIGI1_CLOTH SIGI1_CLOTH]] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released (By similarity). This sigma factor is involved in regulation of cellulosomal genes via an external polysaccharide-sensing mechanism. SigI1 promotes transcription from sigI1 and celS promoters (PubMed:20937888).[HAMAP-Rule:MF_02064]<ref>PMID:20937888</ref> | ||
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== Publication Abstract from PubMed == | |||
The sigma70 family alternative sigmaI factors and their cognate anti-sigmaI factors are widespread in Clostridia and Bacilli and play a role in heat stress response, virulence, and polysaccharide sensing. Multiple sigmaI/anti-sigmaI factors exist in some lignocellulolytic clostridial species, specifically for regulation of components of a multienzyme complex, termed the cellulosome. The sigmaI and anti-sigmaI factors are unique, because the C-terminal domain of sigmaI (SigIC) and the N-terminal inhibitory domain of anti-sigmaI (RsgIN) lack homology to known proteins. Here, we report structure and interaction studies of a pair of sigmaI and anti-sigmaI factors, SigI1 and RsgI1, from the cellulosome-producing bacterium, Clostridium thermocellum. In contrast to other known anti-sigma factors that have N-terminal helical structures, RsgIN has a beta-barrel structure. Unlike other anti-sigma factors that bind both sigma2 and sigma4 domains of the sigma factors, RsgIN binds SigIC specifically. Structural analysis showed that SigIC contains a positively charged surface region that recognizes the promoter -35 region, and the synergistic interactions among multiple interfacial residues result in the specificity displayed by different sigmaI/anti-sigmaI pairs. We suggest that the sigmaI/anti-sigmaI factors represent a distinctive mode of sigma/anti-sigma complex formation, which provides the structural basis for understanding the molecular mechanism of the intricate sigmaI/anti-sigmaI system. | |||
Alternative sigmaI/anti-sigmaI factors represent a unique form of bacterial sigma/anti-sigma complex.,Wei Z, Chen C, Liu YJ, Dong S, Li J, Qi K, Liu S, Ding X, Ortiz de Ora L, Munoz-Gutierrez I, Li Y, Yao H, Lamed R, Bayer EA, Cui Q, Feng Y Nucleic Acids Res. 2019 May 20. pii: 5490815. doi: 10.1093/nar/gkz355. PMID:31106374<ref>PMID:31106374</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
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== References == | == References == | ||
<references/> | <references/> | ||
Revision as of 02:05, 6 June 2019
Solution structure of the Sigma-anti-sigma factor complex RsgI1N-SigI1C from Clostridium thermocellumSolution structure of the Sigma-anti-sigma factor complex RsgI1N-SigI1C from Clostridium thermocellum
Structural highlights
Function[RSGI1_CLOTH] Anti-sigma factor for SigI1. Negatively regulates SigI1 activity through direct interaction (PubMed:20937888). Binding of the polysaccharide substrate to the extracellular C-terminal sensing domain of RsgI1 may induce a conformational change in its N-terminal cytoplasmic region, leading to the release and activation of SigI1 (Probable).[1] [2] [SIGI1_CLOTH] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released (By similarity). This sigma factor is involved in regulation of cellulosomal genes via an external polysaccharide-sensing mechanism. SigI1 promotes transcription from sigI1 and celS promoters (PubMed:20937888).[HAMAP-Rule:MF_02064][3] Publication Abstract from PubMedThe sigma70 family alternative sigmaI factors and their cognate anti-sigmaI factors are widespread in Clostridia and Bacilli and play a role in heat stress response, virulence, and polysaccharide sensing. Multiple sigmaI/anti-sigmaI factors exist in some lignocellulolytic clostridial species, specifically for regulation of components of a multienzyme complex, termed the cellulosome. The sigmaI and anti-sigmaI factors are unique, because the C-terminal domain of sigmaI (SigIC) and the N-terminal inhibitory domain of anti-sigmaI (RsgIN) lack homology to known proteins. Here, we report structure and interaction studies of a pair of sigmaI and anti-sigmaI factors, SigI1 and RsgI1, from the cellulosome-producing bacterium, Clostridium thermocellum. In contrast to other known anti-sigma factors that have N-terminal helical structures, RsgIN has a beta-barrel structure. Unlike other anti-sigma factors that bind both sigma2 and sigma4 domains of the sigma factors, RsgIN binds SigIC specifically. Structural analysis showed that SigIC contains a positively charged surface region that recognizes the promoter -35 region, and the synergistic interactions among multiple interfacial residues result in the specificity displayed by different sigmaI/anti-sigmaI pairs. We suggest that the sigmaI/anti-sigmaI factors represent a distinctive mode of sigma/anti-sigma complex formation, which provides the structural basis for understanding the molecular mechanism of the intricate sigmaI/anti-sigmaI system. Alternative sigmaI/anti-sigmaI factors represent a unique form of bacterial sigma/anti-sigma complex.,Wei Z, Chen C, Liu YJ, Dong S, Li J, Qi K, Liu S, Ding X, Ortiz de Ora L, Munoz-Gutierrez I, Li Y, Yao H, Lamed R, Bayer EA, Cui Q, Feng Y Nucleic Acids Res. 2019 May 20. pii: 5490815. doi: 10.1093/nar/gkz355. PMID:31106374[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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