1. Biochemistry and Chemical Biology
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Amidst multiple binding orientations on fork DNA, Saccharolobus MCM helicase proceeds N-first for unwinding

  1. Himasha M Perera
  2. Michael Trakselis  Is a corresponding author
  1. Baylor University, United States
Research Article
  • Cited 2
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Cite this article as: eLife 2019;8:e46096 doi: 10.7554/eLife.46096


DNA replication requires that the duplex genomic DNA strands be separated; a function that is implemented by ring-shaped hexameric helicases in all Domains. Helicases are composed of two domains, an N- terminal DNA binding domain (NTD) and a C- terminal motor domain (CTD). Replication is controlled by loading of helicases at origins of replication, activation to preferentially encircle one strand, and then translocation to begin separation of the two strands. Using a combination of site-specific DNA footprinting, single-turnover unwinding assays, and unique fluorescence translocation monitoring, we have been able to quantify the binding distribution and the translocation orientation of Saccharolobus (formally Sulfolobus) solfataricus MCM on DNA. Our results show that both the DNA substrate and the C-terminal winged-helix (WH) domain influence the orientation but that translocation on DNA proceeds N-first.

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Author details

  1. Himasha M Perera

    Department of Chemistry and Biochemistry, Baylor University, Waco, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1533-9640
  2. Michael Trakselis

    Department of Chemistry and Biochemistry, Baylor University, Waco, United States
    For correspondence
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7054-8475


National Science Foundation (1613534)

  • Michael Trakselis

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

Reviewing Editor

  1. James M Berger, Johns Hopkins University School of Medicine, United States

Publication history

  1. Received: February 14, 2019
  2. Accepted: October 23, 2019
  3. Accepted Manuscript published: October 29, 2019 (version 1)
  4. Version of Record published: November 5, 2019 (version 2)


© 2019, Perera & Trakselis

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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