Catalysis by site-specific recombinases.

Site-specific recombination reactions bring about controlled rearrangements of DNA molecules by cutting the DNA at precise points and rejoining the ends to new partners. The recombinases that catalyse these reactions can be grouped into two families by amino acid sequence homology. We describe our current understanding of how these proteins catalyse recombination, and show how the catalytic mechanisms of the two families differ.