ATP Ground- and Transition States of Bacterial Enhancer Binding AAA+ ATPases Support Complex Formation with Their Target Protein, σ54

  • Baoyu Chen
  • , Michaeleen Doucleff
  • , David E. Wemmer
  • , Sacha De Carlo
  • , Hector H. Huang
  • , Eva Nogales
  • , Timothy R. Hoover
  • , Elena Kondrashkina
  • , Liang Guo
  • , B. Tracy Nixon

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

Abstract

Transcription initiation by the σ54 form of bacterial RNA polymerase requires hydrolysis of ATP by an enhancer binding protein (EBP). We present SAS-based solution structures of the ATPase domain of the EBP NtrC1 from Aquifex aeolicus in different nucleotide states. Structures of apo protein and that bound to AMPPNP or ADP-BeFx (ground-state mimics), ADP-AlFx (a transition-state mimic), or ADP (product) show substantial changes in the position of the GAFTGA loops that contact polymerase, particularly upon conversion from the apo state to the ADP-BeFx state, and from the ADP-AlFx state to the ADP state. Binding of the ATP analogs stabilizes the oligomeric form of the ATPase and its binding to σ54, with ADP-AlFx having the largest effect. These data indicate that ATP binding promotes a conformational change that stabilizes complexes between EBPs and σ54, while subsequent hydrolysis and phosphate release drive the conformational change needed to open the polymerase/promoter complex.

Original languageEnglish (US)
Pages (from-to)429-440
Number of pages12
JournalStructure
Volume15
Issue number4
DOIs
StatePublished - Apr 2007

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Molecular Biology

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