Passing the baton in base excision repair

Apurinic/apyrmidinic endonuclease 1 (APE1) plays a central role in DNA repair by cleaving the DNA backbone 5′ of AP sites that result from removal of damaged bases. New structural findings on APE1–DNA cocrystals provide insights into how this enzyme binds and cleaves its substrate and how, like one member in an efficient relay team, it coordinates potentially dangerous steps in the base excision repair pathway.