title: Mechanism of action of the Escherichia coli phage shock protein PspA in repression of the AAA family transcription factor PspF.
abstract: 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.
authors.affiliation: Department of Biological Sciences, Imperial College of Science Technology and Medicine, Biomedical Sciences Building, Imperial College Road, London SW7 2AZ, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Elderkin
authors.forename: Susan
authors.initials: S
authors.lastname: Jones
authors.forename: Jörg
authors.initials: J
authors.lastname: Schumacher
authors.forename: David
authors.initials: D
authors.lastname: Studholme
authors.forename: Martin
authors.initials: M
authors.lastname: Buck
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D051877:RNA Polymerase Sigma 54; D012808:Sigma Factor / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; C098954:PspF protein, E coli; D012808:Sigma Factor; D015534:Trans-Activators; C069816:phage shock protein, Bacteria; C497751:rpoN protein, E coli; D000255:Adenosine Triphosphate; D004247:DNA; D012321:DNA-Directed RNA Polymerases; D051877:RNA Polymerase Sigma 54; D000251:Adenosine Triphosphatases