1. Structural Biology and Molecular Biophysics
  2. Chromosomes and Gene Expression
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Mechanism of environmentally driven conformational changes that modulate H-NS DNA bridging activity

  1. Ramon A van der Valk
  2. Jocelyne Vreede
  3. Liang Qin
  4. Geri F Moolenaar
  5. Andreas Hofmann
  6. Nora Goosen
  7. Remus T Dame  Is a corresponding author
  1. Leiden University, Netherlands
  2. University of Amsterdam, Netherlands
  3. University of Heidelberg, Germany
Research Article
  • Cited 29
  • Views 1,490
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Cite this article as: eLife 2017;6:e27369 doi: 10.7554/eLife.27369

Abstract

Bacteria frequently need to adapt to altered environmental conditions. Adaptation requires changes in gene expression, often mediated by global regulators of transcription. The nucleoid-associated protein H‑NS is a key global regulator in Gram-negative bacteria, and is believed to be a crucial player in bacterial chromatin organization via its DNA bridging activity. H‑NS activity in vivo is modulated by physico-chemical factors (osmolarity, pH, temperature) and interaction partners. Mechanistically it is unclear how functional modulation of H-NS by such factors is achieved. Here, we show that a diverse spectrum of H-NS modulators alter the DNA bridging activity of H-NS. Changes in monovalent and divalent ion concentrations drive an abrupt switch between a bridging and non-bridging DNA binding mode. Similarly, synergistic and antagonistic co-regulators modulate the DNA bridging efficiency. Structural studies suggest a conserved mechanism: H-NS switches between a "closed" and an "open", bridging competent, conformation driven by environmental cues and interaction partners.

Article and author information

Author details

  1. Ramon A van der Valk

    Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  2. Jocelyne Vreede

    Computational Chemistry, van 't Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  3. Liang Qin

    Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  4. Geri F Moolenaar

    Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  5. Andreas Hofmann

    Institute for Theoretical Physics, University of Heidelberg, Heidelberg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  6. Nora Goosen

    Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  7. Remus T Dame

    Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands
    For correspondence
    rtdame@chem.leidenuniv.nl
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9863-1692

Funding

NanonextNL of the Government of the Netherland and 130 partners

  • Ramon A van der Valk
  • Geri F Moolenaar
  • Remus T Dame

Netherlands Organisation for Scientific Research (VIDI 864.08.001)

  • Ramon A van der Valk
  • Geri F Moolenaar
  • Nora Goosen
  • Remus T Dame

Netherlands Organisation for Scientific Research (Athena grant 700.58.802)

  • Jocelyne Vreede

Human Frontier Science Program (RGP0014/2014)

  • Andreas Hofmann
  • Remus T Dame

China Scholarship Council (No. 201506880001)

  • Liang Qin

Netherlands Organisation for Scientific Research (VICI 016.160.613)

  • Remus T Dame

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Gisela Storz, National Institute of Child Health and Human Development, United States

Publication history

  1. Received: April 3, 2017
  2. Accepted: September 25, 2017
  3. Accepted Manuscript published: September 26, 2017 (version 1)
  4. Version of Record published: October 18, 2017 (version 2)

Copyright

© 2017, van der Valk et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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