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Molecular flexibility of DNA as a key determinant of RAD 51 recruitment

DOI: 10.15252/embj.2019103002 DOI Help

Authors: Federico Paoletti (University of Oxford) , Afaf H. El-Sagheer (University of Oxford; Suez University) , Jun Allard (University of California, Irvine) , Tom Brown (University of Oxford) , Omer Dushek (University of Oxford) , Fumiko Esashi (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: The Embo Journal , VOL 39

State: Published (Approved)
Published: April 2020

Open Access Open Access

Abstract: The timely activation of homologous recombination is essential for the maintenance of genome stability, in which the RAD51 recombinase plays a central role. Biochemically, human RAD51 polymerises faster on single‐stranded DNA (ssDNA) compared to double‐stranded DNA (dsDNA), raising a key conceptual question: how does it discriminate between them? In this study, we tackled this problem by systematically assessing RAD51 binding kinetics on ssDNA and dsDNA differing in length and flexibility using surface plasmon resonance. By directly fitting a mechanistic model to our experimental data, we demonstrate that the RAD51 polymerisation rate positively correlates with the flexibility of DNA. Once the RAD51‐DNA complex is formed, however, RAD51 remains stably bound independent of DNA flexibility, but rapidly dissociates from flexible DNA when RAD51 self‐association is perturbed. This model presents a new general framework suggesting that the flexibility of DNA, which may increase locally as a result of DNA damage, plays an important role in rapidly recruiting repair factors that multimerise at sites of DNA damage.

Journal Keywords: double‐stranded DNA; mathematical model; RAD51; single‐stranded DNA; surface plasmon resonance

Subject Areas: Biology and Bio-materials, Chemistry

Instruments: B21-High Throughput SAXS

Added On: 20/04/2021 14:01


Discipline Tags:

Life Sciences & Biotech Genetics Health & Wellbeing Chemistry Biochemistry

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)