Switch-like control of helicase processivity by single-stranded DNA binding protein

  1. Barbara Stekas
  2. Steve Yeo
  3. Alice Troitskaia
  4. Masayoshi Honda
  5. Sei Sho
  6. Maria Spies
  7. Yann R Chemla  Is a corresponding author
  1. University of Illinois at Urbana-Champaign, United States
  2. University of Iowa, United States

Abstract

Helicases utilize NTP hydrolysis to translocate along single-stranded nucleic acids (NA) and unwind the duplex. In the cell, helicases function in the context of other NA-associated proteins such as single-stranded DNA binding proteins. Such encounters regulate helicase function, although the underlying mechanisms remain largely unknown. F. acidarmanus XPD helicase serves as a model for understanding the molecular mechanisms of Superfamily 2B helicases, and its activity is enhanced by the cognate single-stranded DNA binding protein RPA2. Here, optical trap measurements of the unwinding activity of a single XPD helicase in the presence of RPA2 reveal a mechanism in which XPD interconverts between two states with different processivities and transient RPA2 interactions stabilize the more processive state, activating a latent 'processivity switch' in XPD. A point mutation at a regulatory DNA binding site on XPD similarly activates this switch. These findings provide new insights on mechanisms of helicase regulation by accessory proteins.

Data availability

Summary data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 2, 3, 4, 5 and corresponding figure supplements.

Article and author information

Author details

  1. Barbara Stekas

    Physics, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    No competing interests declared.
  2. Steve Yeo

    Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    No competing interests declared.
  3. Alice Troitskaia

    Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    No competing interests declared.
  4. Masayoshi Honda

    Department of Biochemistry, University of Iowa, Iowa City, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8920-6301
  5. Sei Sho

    Department of Biochemistry, University of Iowa, Iowa City, United States
    Competing interests
    No competing interests declared.
  6. Maria Spies

    Department of Biochemistry, University of Iowa, Iowa City, United States
    Competing interests
    Maria Spies, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7375-8037
  7. Yann R Chemla

    Physics, University of Illinois at Urbana-Champaign, Urbana, United States
    For correspondence
    ychemla@illinois.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9167-0234

Funding

National Institutes of Health (R01 GM120353)

  • Yann R Chemla

National Institutes of Health (R35 GM131704)

  • Maria Spies

National Institutes of Health (R01 GM120353)

  • Barbara Stekas

National Institutes of Health (R35 GM131704)

  • Masayoshi Honda

National Institutes of Health (R01 GM120353)

  • Steve Yeo

National Institutes of Health (R01 GM120353)

  • Alice Troitskaia

National Institutes of Health (R35 GM131704)

  • Sei Sho

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: June 29, 2020
  2. Accepted: March 18, 2021
  3. Accepted Manuscript published: March 19, 2021 (version 1)
  4. Version of Record published: March 26, 2021 (version 2)

Copyright

© 2021, Stekas 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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  1. Barbara Stekas
  2. Steve Yeo
  3. Alice Troitskaia
  4. Masayoshi Honda
  5. Sei Sho
  6. Maria Spies
  7. Yann R Chemla
(2021)
Switch-like control of helicase processivity by single-stranded DNA binding protein
eLife 10:e60515.
https://doi.org/10.7554/eLife.60515

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