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Updated: Dec 27, 2025

Real-time Observation of the DNA Strand Exchange Reaction Mediated by Rad51
Published on: February 13, 2019
RAD51 discrimination between single- and double-strand DNA: a matter of flexibility and enthalpy
Shyamal Subramanyam1, Maria Spies2
1Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Abstract:
In selecting ssDNA over dsDNA, the RAD51 DNA strand exchange protein has to overcome the entropy associated with straightening of single-strand DNA upon nucleoprotein filament formation. New work in The EMBO Journal (Paoletti et al, 2020), combined biophysical analysis of the RAD51-ssDNA interaction with mathematical modeling to show that the flexibility of DNA positively correlates with nucleation and extension of the RAD51 nucleoprotein filament and that the entropic penalty associated with restricting ssDNA flexibility is offset by a strong RAD51-RAD51 interaction within the nucleoprotein filament.
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