pH-dependent conformational switch activates the inhibitor of transcription elongation

Oleg Laptenko, Seung Sup Kim, Jookyung Lee, Marina Starodubtseva, Fellipe Cava, Jose Berenguer, Xiang Peng Kong, Sergei Borukhov

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Abstract

Gfh1, a transcription factor from Thermus thermophilus, inhibits all catalytic activities of RNA polymerase (RNAP). We characterized the Gfh1 structure, function and possible mechanism of action and regulation. Gfh1 inhibits RNAP by competing with NTPs for coordinating the active site Mg 2+ ion. This coordination requires at least two aspartates at the tip of the Gfh1 N-terminal coiled-coil domain (NTD). The overall structure of Gfh1 is similar to that of the Escherichia coli transcript cleavage factor GreA, except for the flipped orientation of the C-terminal domain (CTD). We show that depending on pH, Gfh1-CTD exists in two alternative orientations. At pH above 7, it assumes an inactive 'flipped' orientation seen in the structure, which prevents Gfh1 from binding to RNAP. At lower pH, Gfh1-CTD switches to an active 'Gre-like' orientation, which enables Gfh1 to bind to and inhibit RNAP.

Original languageEnglish (US)
Pages (from-to)2131-2141
Number of pages11
JournalEMBO Journal
Volume25
Issue number10
DOIs
StatePublished - May 17 2006

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All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Laptenko, O., Kim, S. S., Lee, J., Starodubtseva, M., Cava, F., Berenguer, J., Kong, X. P., & Borukhov, S. (2006). pH-dependent conformational switch activates the inhibitor of transcription elongation. EMBO Journal, 25(10), 2131-2141. https://doi.org/10.1038/sj.emboj.7601094