Pseudomonas aeruginosa SutA wedges RNAP lobe domain open to facilitate promoter DNA unwinding

Nat Commun. 2022 Jul 20;13(1):4204. doi: 10.1038/s41467-022-31871-7.

Abstract

Pseudomonas aeruginosa (Pae) SutA adapts bacteria to hypoxia and nutrition-limited environment during chronic infection by increasing transcription activity of an RNA polymerase (RNAP) holoenzyme comprising the stress-responsive σ factor σS (RNAP-σS). SutA shows no homology to previously characterized RNAP-binding proteins. The structure and mode of action of SutA remain unclear. Here we determined cryo-EM structures of Pae RNAP-σS holoenzyme, Pae RNAP-σS holoenzyme complexed with SutA, and Pae RNAP-σS transcription initiation complex comprising SutA. The structures show SutA pinches RNAP-β protrusion and facilitates promoter unwinding by wedging RNAP-β lobe open. Our results demonstrate that SutA clears an energetic barrier to facilitate promoter unwinding of RNAP-σS holoenzyme.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / metabolism
  • DNA / metabolism
  • DNA-Directed RNA Polymerases* / metabolism
  • Holoenzymes / metabolism
  • Pseudomonas aeruginosa* / metabolism
  • Sigma Factor / metabolism
  • Transcription, Genetic

Substances

  • Bacterial Proteins
  • Holoenzymes
  • Sigma Factor
  • DNA
  • DNA-Directed RNA Polymerases