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PLoS One. 2015 Jan 21;10(1):e0115611. doi: 10.1371/journal.pone.0115611. eCollection 2015.

Dynamic growth and shrinkage govern the pH dependence of RecA filament stability.

Author information

1
Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Korea.
2
Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
3
Kavli Institute of NanoScience, Department of BioNanoScience, Delft University of Technology, Delft, The Netherlands.
4
Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America; Howard Hughes Medical Institute, Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.

Abstract

RecA proteins form a long stable filament on a single-stranded DNA and catalyze strand exchange reaction. The stability of RecA filament changes dramatically with pH, yet its detailed mechanism is not known. Here, using a single molecule assay, we determined the binding and dissociation rates of RecA monomers at the filament ends at various pH. The pH-induced rate changes were moderate but occurred in opposite directions for binding and dissociation, resulting in a substantial increase in filament stability in lower pH. The highly charged residues in C-terminal domain do not contribute to the pH dependent stability. The stability enhancement of RecA filament in low pH may help the cell to cope with acidic stress by fine-tuning of the binding and dissociation rates without losing the highly dynamic nature of the filament required for strand exchange.

PMID:
25608006
PMCID:
PMC4301630
DOI:
10.1371/journal.pone.0115611
[Indexed for MEDLINE]
Free PMC Article

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