ATP half-sites in RadA and RAD51 recombinases bind nucleotides.

Homologous recombination is essential for repair of DNA double-strand breaks. Central to this process is a family of recombinases, including archeal RadA and human RAD51, which form nucleoprotein filaments on damaged single-stranded DNA ends and facilitate their ATP-dependent repair. ATP binding and hydrolysis are dependent on the formation of a nucleoprotein filament comprising RadA/RAD51 and single-stranded DNA, with ATP bound between adjacent protomers.