RAD51 D-loop structures reveal the mechanism of eukaryotic RAD51-mediated strand exchange.

ABSTRACT: Strand exchange is a key step in homologous recombination, enabling template-based repair of DNA double-strand breaks. Eukaryotic RAD51 forms an ATP-dependent helical presynaptic filament on single-stranded DNA (ssDNA), which then searches for homologous double-stranded DNA (dsDNA), and catalyzes the strand exchange to form a D-loop in an ATP hydrolysis-independent manner. The molecular mechanism by which RAD51 facilitates dsDNA unwinding and pairing remains unclear. Here, we present cryo-EM structures of RAD51 mini-filaments bound to homologous dsDNA, capturing five intermediates from dsDNA recruitment to D-loop formation. These structures, together with molecular dynamics simulations, suggest a stepwise mechanism: the conserved N-terminal domain (NTD) recruits and bends the dsDNA, weaken

SUBMITTER: Luo SC 

PROVIDER: S-EPMC12783270 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature