Dynamic aspects of filament formation: ReCa and Rad51 Filaments
- RecA is the prototypic recombinase protein essential for homologous recombination.
- Rec and Rad51 form helical filaments on single-stranded DNA
RecA is able to form helical filaments on single-stranded DNA, ATPase activity of RecA allows it to reorganize after random nucleation events to form long continuous filaments. Using magnetic tweezers we were able to study the dynamics of this reaction in real time and at the single molecule level.
Using this assay we find that:
- RecA reorganization by ATP hydrolysis is essential to form long continuous filaments on ssDNA.
- RecA filaments can reversibly switch between an extended and collapsed state upon ATP binding and hydrolysis.
- The force dependence of RecA disassembly matches a mechanism where RecA dissociates one monomer at a time.
Reference:
M.T.J. van Loenhout, T. van der Heijden, R. Kanaar, C. Wyman, C. Dekker
Dynamics of RecA filaments on single stranded DNA
Nucleic Acids Research 37, 4089-4099 (2009)
