DNA cleaving modes in minor groove of DNA helix by esperamicin and calicheamicin antitumor antibiotics.

This study examines and compares DNA cleavage modes by several esperamicin derivatives and calicheamicin. We found that the deoxyfucose-anthranilate moiety is a key factor to determine their DNA cutting modes. Probably, the bulky moiety hinders the abstraction of hydrogen atom from deoxyribose by the C-1 carbon radical of phenylene diradical. On the basis of the experimental results, detailed DNA cleaving modes in DNA minor groove by esperamicin and calicheamicin have been discussed.