The mechanism of topoisomerase action involves making a transient break in DNA, which, if it occurs near another DNA lesion, can persist, with the topoisomerase attached the 3′ or 5′ end by a phosphotyrosyl bond. If the DNA termini are not liberated from the topoisomerase, cancer and neurodegenerative disease may result. A human enzyme that cleaves 3′-phosphotyrosyl bonds has already been identified; a complementary enzyme that cleaves 5′-phosphotyrosyl bonds is now reported.
- Felipe Cortes Ledesma
- Sherif F. El Khamisy
- Keith W. Caldecott
