Quantitative analysis of the kinetics of end-dependent disassembly of RecA filaments from ssDNA

Tanya A. Arenson, Oleg V. Tsodikov, Michael M. Cox

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

On linear single-stranded DNA, RecA filaments assemble and disassemble in the 5' to 3' direction. Monomers (or other units) associate at one end and dissociate from the other. ATP hydrolysis occurs throughout the filament. Dissociation can result when ATP is hydrolyzed by the monomer at the disassembly end. We have developed a comprehensive model for the end-dependent filament disassembly process. The model accounts not only for disassembly, but also for the limited reassembly that occurs as DNA is vacated by disassembling filaments. The overall process can be monitored quantitatively by following the resulting decline in DNA-dependent ATP hydrolysis. The rate of disassembly is highly pH depen dent, being negligible at pH 6 and reaching a maximum at pH values above 7.5. The rate of disassembly is not significantly affected by the concentration of free RecA protein within the experimental uncertainty. For filaments on single-stranded DNA, the monomer k(cat) for ATP hydrolysis is 30 min-1, and disassembly proceeds at a maximum rate of 60-70 monomers per minute per filament end. The latter rate is that predicted if the ATP hydrolytic cycles of adjacent monomers are not coupled in any way.

Original languageEnglish
Pages (from-to)391-401
Number of pages11
JournalJournal of Molecular Biology
Volume288
Issue number3
DOIs
StatePublished - May 7 1999

Bibliographical note

Funding Information:
This work was supported by grant GM32335 from the National Institutes of Health. The authors thank M. Thomas Record Jr and Ronald T. Raines for assistance in the early stages of the development of the quantitative treatment of filament disassembly. Oleg Tsodikov was supported by grant GM23467 (to M. Thomas Record Jr) from the National Institutes of Health.

Keywords

  • Assembly
  • Disassembly
  • Filament
  • Kinetic analysis
  • RecA protein

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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