title: Dynamic growth and shrinkage govern the pH dependence of RecA filament stability.
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.
authors.affiliation: Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Korea.
authors.forename: Sung Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America.
authors.forename: Jeehae
authors.initials: J
authors.lastname: Park
authors.affiliation: Kavli Institute of NanoScience, Department of BioNanoScience, Delft University of Technology, Delft, The Netherlands.
authors.forename: Chirlmin
authors.initials: C
authors.lastname: Joo
authors.affiliation: Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, Seoul, Korea.
authors.forename: Doseok
authors.initials: D
authors.lastname: Kim
authors.affiliation: 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.
authors.forename: Taekjip
authors.initials: T
authors.lastname: Ha
mesh_terms: D006863:Hydrogen-Ion Concentration; D046912:Multiprotein Complexes / Q000737:chemistry*; D011938:Rec A Recombinases / Q000737:chemistry*
chemical_list: D046912:Multiprotein Complexes; D011938:Rec A Recombinases