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Updated: Jun 24, 2026

Artificial RNA Polymerase II Elongation Complexes for Dissecting Co-transcriptional RNA Processing Events
Published on: May 13, 2019
Coupling sigma factor conformation to RNA polymerase reorganisation for DNA melting
Patricia C Burrows1, Nicolas Joly, Wendy V Cannon
1Division of Biology, Department of Life Sciences, Faculty of Natural Sciences, Sir Alexander Fleming Building, Imperial College London, London SW7 2AZ, UK.
Abstract:
ATP-driven remodelling of initial RNA polymerase (RNAP) promoter complexes occurs as a major post recruitment strategy used to control gene expression. Using a model-enhancer-dependent bacterial system (sigma54-RNAP, Esigma54) and a slowly hydrolysed ATP analogue (ATPgammaS), we provide evidence for a nucleotide-dependent temporal pathway leading to DNA melting involving a small set of sigma54-DNA conformational states. We demonstrate that the ATP hydrolysis-dependent remodelling of Esigma54 occurs in at least two distinct temporal steps. The first detected remodelling phase results in changes in the interactions between the promoter specificity sigma54 factor and the promoter DNA. The second detected remodelling phase causes changes in the relationship between the promoter DNA and the core RNAP catalytic beta/beta' subunits, correlating with the loading of template DNA into the catalytic cleft of RNAP. It would appear that, for Esigma54 promoters, loading of template DNA within the catalytic cleft of RNAP is dependent on fast ATP hydrolysis steps that trigger changes in the beta' jaw domain, thereby allowing acquisition of the open complex status.
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