Switch-like control of helicase processivity by single-stranded DNA binding protein
- University of Illinois at Urbana-Champaign, United States
- 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
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.
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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Switch-like control of helicase processivity by single-stranded DNA binding protein
eLife 10:e60515.
https://doi.org/10.7554/eLife.60515
