Identification of DNA degradation products by antitumor antibiotic, esperamicin

Esperamicin A1 is a DNA-damaging agent characterized by a unique ten-membered ene-diyne core. We studied the detailed reaction mechanism by using synthetic DNA oligomers. The cleavage site and activity depend on the sequence of the oligomers. d(GGATCC) and d(GGTACC) were cleaved by the drug while d(CCATGG) and d(CCTAGG) were not cleaved under the present conditions. d(GGTACC) gave two major 5'-fragments. The result of partial nuclease digestion experiments suggests that these products are trimer and pentamer with a modified 3'-end.