Figure 1.

Structure of Adriamycin showing its covalent and noncovalent bonding array to, respectively, the c-strand and the n-strand of DNA. Rings B–D are intercalated into duplex DNA from the minor groove, and drug-DNA association, whether covalent or noncovalent, is mediated through guanine N2 amino groups on either strand. The covalent methylene linkage between Adriamycin-N3′ and c-strand guanine N2 derives from formaldehyde.