Mechanism of action of the Escherichia coli phage shock protein PspA in repression of the AAA family transcription factor PspF

J Mol Biol. 2002 Jun 28;320(1):23-37. doi: 10.1016/S0022-2836(02)00404-7.


The PspA protein, a negative regulator of the Escherichia coli phage shock psp operon, is produced when virulence factors are exported through secretins in many Gram-negative pathogenic bacteria and its homologue in plants, VIPP1, plays a critical role in thylakoid biogenesis, essential for photosynthesis. Activation of transcription by the enhancer-dependent bacterial sigma(54) containing RNA polymerase occurs through ATP hydrolysis-driven protein conformational changes enabled by activator proteins that belong to the large AAA(+) mechanochemical protein family. We show that PspA directly and specifically acts upon and binds to the AAA(+) domain of the PspF transcription activator. Interactions involving PspF and nucleotide are changed by the action of PspA. These changes and the complexes that form between PspF and PspA can explain how PspA exerts its negative effects upon transcription activated by PspF, and are of significance when considering how activities of other AAA(+) proteins might be controlled.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • DNA / genetics
  • DNA / metabolism
  • DNA-Binding Proteins*
  • DNA-Directed RNA Polymerases / metabolism
  • Escherichia coli / genetics
  • Escherichia coli / metabolism*
  • Escherichia coli Proteins*
  • Gene Expression Regulation, Bacterial*
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism*
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA Polymerase Sigma 54
  • Sigma Factor / metabolism
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • Transcription, Genetic / physiology


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Escherichia coli Proteins
  • Heat-Shock Proteins
  • Membrane Proteins
  • PspF protein, E coli
  • Sigma Factor
  • Trans-Activators
  • phage shock protein, Bacteria
  • rpoN protein, E coli
  • Adenosine Triphosphate
  • DNA
  • DNA-Directed RNA Polymerases
  • RNA Polymerase Sigma 54
  • Adenosine Triphosphatases