Structural Basis for Converting a General Transcription Factor into an Operon-Specific Virulence Regulator

Georgiy A. Belogurov, Marina N. Vassylyeva, Vladimir Svetlov, Sergiy Klyuyev, Nick V. Grishin, Dmitry G Vassylyev, Irina Artsimovitch

Research output: Contribution to journalArticle

142 Scopus citations

Abstract

RfaH, a paralog of the general transcription factor NusG, is recruited to elongating RNA polymerase at specific regulatory sites. The X-ray structure of Escherichia coli RfaH reported here reveals two domains. The N-terminal domain displays high similarity to that of NusG. In contrast, the α-helical coiled-coil C domain, while retaining sequence similarity, is strikingly different from the β barrel of NusG. To our knowledge, such an all-β to all-α transition of the entire domain is the most extreme example of protein fold evolution known to date. Both N domains possess a vast hydrophobic cavity that is buried by the C domain in RfaH but is exposed in NusG. We propose that this cavity constitutes the RNA polymerase-binding site, which becomes unmasked in RfaH only upon sequence-specific binding to the nontemplate DNA strand that triggers domain dissociation. Finally, we argue that RfaH binds to the β′ subunit coiled coil, the major target site for the initiation σ factors.

Original languageEnglish (US)
Pages (from-to)117-129
Number of pages13
JournalMolecular cell
Volume26
Issue number1
DOIs
StatePublished - Apr 13 2007

Keywords

  • DNA
  • MICROBIO

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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    Belogurov, G. A., Vassylyeva, M. N., Svetlov, V., Klyuyev, S., Grishin, N. V., Vassylyev, DG., & Artsimovitch, I. (2007). Structural Basis for Converting a General Transcription Factor into an Operon-Specific Virulence Regulator. Molecular cell, 26(1), 117-129. https://doi.org/10.1016/j.molcel.2007.02.021