Rad51/RecA protein families and the associated proteins in eukaryotes.

Searching for homologous DNA molecules, pairing of the molecules and exchange of the strand with one of a counterpart duplex molecule are a central process for homologous recombination. RecA protein in Esherichia coli has been known to play a pivotal role in the processes. The recA gene was identified by A.J. Clark and his colleagues more than w x 30 years ago 1 and the first biochemical activities of the protein were described in 1978 by Roberts et w x w x al. 2 and Ogawa et al. 3 independently. Since then, the RecA protein has been the main focus in w x the field studying recombination 4,5 . The RecA Ž . protein binds to single-stranded DNA ssDNA in the presence of a high-energy nucleotide cofactor such as ATP and forms a typical right-handed helical