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Molecular flexibility of DNA as a key determinant of RAD 51 recruitment
Author(s) -
Paoletti Federico,
ElSagheer Afaf H,
Allard Jun,
Brown Tom,
Dushek Omer,
Esashi Fumiko
Publication year - 2020
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.15252/embj.2019103002
Subject(s) - rad51 , biology , dna , homologous recombination , dna repair , dna damage , flexibility (engineering) , replication protein a , recombinase , microbiology and biotechnology , genetics , computational biology , biophysics , dna binding protein , recombination , gene , transcription factor , statistics , mathematics
The timely activation of homologous recombination is essential for the maintenance of genome stability, in which the RAD 51 recombinase plays a central role. Biochemically, human RAD 51 polymerises faster on single‐stranded DNA (ss DNA ) compared to double‐stranded DNA (ds DNA ), raising a key conceptual question: how does it discriminate between them? In this study, we tackled this problem by systematically assessing RAD 51 binding kinetics on ss DNA and ds DNA differing in length and flexibility using surface plasmon resonance. By directly fitting a mechanistic model to our experimental data, we demonstrate that the RAD 51 polymerisation rate positively correlates with the flexibility of DNA . Once the RAD 51‐ DNA complex is formed, however, RAD 51 remains stably bound independent of DNA flexibility, but rapidly dissociates from flexible DNA when RAD 51 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.