A hyper-mutant of the unusual σ70-Pr promoter bypasses synergistic ppGpp/DksA co-stimulation
2011 (English)In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 39, no 14, 5853-5865 p.Article in journal (Refereed) Published
The activities of promoters can be temporally and conditionally regulated by mechanisms other than classical DNA-binding repressors and activators. One example is the inherently weak σ70-dependent Pr promoter that ultimately controls catabolism of phenolic compounds. The activity of Pr is up-regulated through the joint action of ppGpp and DksA that enhance the performance of RNA polymerase at this promoter. Here, we report a mutagenesis analysis that revealed substantial differences between Pr and other ppGpp/DksA co-stimulated promoters. In vitro transcription and RNA polymerase binding assays show that it is the T at the −11 position of the extremely suboptimal −10 element of Pr that underlies both poor binding of σ70-RNAP and a slow rate of open complex formation—the process that is accelerated by ppGpp and DksA. Our findings support the idea that collaborative action of ppGpp and DksA lowers the rate-limiting transition energy required for conversion between intermediates on the road to open complex formation.
Place, publisher, year, edition, pages
London: Information Retrieval Ltd , 2011. Vol. 39, no 14, 5853-5865 p.
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:umu:diva-43229DOI: 10.1093/nar/gkr167PubMedID: 21447563OAI: oai:DiVA.org:umu-43229DiVA: diva2:412394