Two distinct conformational states define the interaction of human RAD51‐ATP with single‐stranded DNA

Ineke Brouwer (1) , Tommaso Moschetti (2) , Andrea Candelli (1) , Edwige B Garcin (3) , Mauro Modesti (3) , Luca Pellegrini (2) , Gijs Jl Wuite (1) , Erwin Jg Peterman (1)

1 VU - Vrije Universiteit Amsterdam [Amsterdam]
2 CAM - University of Cambridge [UK]
3 CRCM - Centre de Recherche en Cancérologie de Marseille

An essential mechanism for repairing DNA double-strand breaks is homologous recombination (HR). One of its core catalysts is human RAD51 (hRAD51), which assembles as a helical nucleoprotein filament on single-stranded DNA, promoting DNA-strand exchange. Here, we study the interaction of hRAD51 with single-stranded DNA using a single-molecule approach. We show that ATP-bound hRAD51 filaments can exist in two different states with different contour lengths and with a free-energy difference of~4 k B T per hRAD51 monomer. Upon ATP hydrolysis, the filaments convert into a disassembly-competent ADP-bound configuration. In agreement with the single-molecule analysis, we demonstrate the presence of two distinct protomer interfaces in the crystal structure of a hRAD51-ATP filament, providing a structural basis for the two conformational states of the filament. Together, our findings provide evidence that hRAD51-ATP filaments can exist in two inter-convertible conformational states, which might be functionally relevant for DNA homology recognition and strand exchange.

Keywords: DNA repair; homologous recombination; RAD51; single-stranded DNA Subject Categories DNA Replication; Repair & Recombination; Structural Biology

Domains: Life Sciences [q-bio]

Ineke Brouwer, Tommaso Moschetti, Andrea Candelli, Edwige B Garcin, Mauro Modesti, et al.. Two distinct conformational states define the interaction of human RAD51‐ATP with single‐stranded DNA. EMBO Journal, 2018, 37 (7), ⟨10.15252/embj.201798162⟩. ⟨hal-01789423⟩