1. Biochemistry and Chemical Biology
  2. Structural Biology and Molecular Biophysics
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Mechanisms of opening and closing of the bacterial replicative helicase

  1. Jillian Chase
  2. Andrew Catalano
  3. Alex J Noble
  4. Edward T Eng
  5. Paul D B Olinares
  6. Kelley Molloy
  7. Danaya Pakotiprapha
  8. Martin Samuels
  9. Brian Chait
  10. Amedee des Georges  Is a corresponding author
  11. David Jeruzalmi  Is a corresponding author
  1. City College of New York, United States
  2. New York Structural Biology Center, United States
  3. The Rockefeller University, United States
  4. Mahidol University, Thailand
  5. Harvard University, United States
Research Article
  • Cited 7
  • Views 3,121
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Cite this article as: eLife 2018;7:e41140 doi: 10.7554/eLife.41140

Abstract

Assembly of bacterial ring-shaped hexameric replicative helicases on single-stranded (ss) DNA requires specialized loading factors. However, mechanisms implemented by these factors during opening and closing of the helicase, which enable and restrict access to an internal chamber, are not known. Here, we investigate these mechanisms in the Escherichia coli DnaB helicase•bacteriophage λ helicase loader (λP) complex. We show that five copies of λP bind at DnaB subunit interfaces and reconfigure the helicase into an open spiral conformation that is intermediate to previously observed closed ring and closed spiral forms; reconfiguration also produces openings large enough to admit ssDNA into the inner chamber. The helicase is also observed in a restrained inactive configuration that poises it to close on activating signal, and transition to the translocation state. Our findings provide insights into helicase opening, delivery to the origin and ssDNA entry, and closing in preparation for translocation.

Data availability

Cryogenic electron microscopy maps have been deposited with the EMDB under accession number EMD-7076Atomic coordinates have been deposited with the PDB under the accession code 6BBM

The following data sets were generated

Article and author information

Author details

  1. Jillian Chase

    Department of Chemistry and Biochemistry, City College of New York, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Andrew Catalano

    Department of Chemistry and Biochemistry, City College of New York, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Alex J Noble

    National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8634-2279
  4. Edward T Eng

    National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8014-7269
  5. Paul D B Olinares

    Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Kelley Molloy

    Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Danaya Pakotiprapha

    Department of Biochemistry, Mahidol University, Bangkok, Thailand
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5017-8283
  8. Martin Samuels

    Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Brian Chait

    Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Amedee des Georges

    Department of Chemistry and Biochemistry, City College of New York, New York, United States
    For correspondence
    amedee.desgeorges@asrc.cuny.edu
    Competing interests
    The authors declare that no competing interests exist.
  11. David Jeruzalmi

    Department of Chemistry and Biochemistry, City College of New York, New York, United States
    For correspondence
    dj@ccny.cuny.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5886-1370

Funding

National Institutes of Health (GM084162)

  • David Jeruzalmi

National Science Foundation (MCB 1818255)

  • David Jeruzalmi

National Institutes of Health (5G12MD007603-30)

  • David Jeruzalmi

Simons Foundation (SF349247)

  • Edward T Eng

Agouron Institute (F00316)

  • Edward T Eng

National Institutes of Health (OD019994)

  • Edward T Eng

Department of Education and Training (PA200A150068)

  • Jillian Chase

National Institutes of Health (P41 GM103314)

  • Brian Chait

National Institutes of Health (P41 GM109824)

  • Brian Chait

National Institutes of Health (F32GM128303)

  • Alex J Noble

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

Reviewing Editor

  1. Michael R Botchan, University of California, Berkeley, United States

Publication history

  1. Received: August 15, 2018
  2. Accepted: December 21, 2018
  3. Accepted Manuscript published: December 24, 2018 (version 1)
  4. Version of Record published: February 26, 2019 (version 2)

Copyright

© 2018, Chase 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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