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MS2-Affinity Purification Coupled with RNA Sequencing in Gram-Positive Bacteria
Published on: February 23, 2021
Evidence for self-association of the alternative sigma factor σ54
Massimo Sabbatini1, Alessandro Vezzoli, Mario Milani
1Department of Life Sciences, Università degli Studi di Milano, Milan, Italy.
Abstract:
Sigma factor σ(54) has a distinct modus operandi for mediating the activation of bacterial RNA polymerase (RNAP) at promoter recognition motifs 12 and 24 bp upstream from transcription start sites. σ(54) was thought to act as monomer in all transcription steps. However, we provide evidence that σ(54) of Pseudomonas putida interacts stably with itself. The interface between monomers involves contacts in σ(54) regions I and III, sequences that play key roles in the transcription activation of σ(54)-RNAP holoenzyme. These roles include interactions with activator proteins and the -12 and -24 motifs. In particular, we detected inter-monomer contacts between region I, and between region I and the C-terminal portion of region III. Our results suggest a new auto-antagonistic regulatory state of σ(54).
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