text: The cyclization of the enediyne functional group creates a transient reactive 1,4-benzenoid diradical that acts as a nucleophile and attacks electrophiles in order to achieve a more stable form. In biological systems, once the diradical is positioned in the minor groove of double-stranded DNA, it abstracts two hydrogen atoms from the sugars opposite strands at either the C1, C4, or C5 positions. The DNA radicals that form can then cause interstrand crosslinks or react with O, leading to double- or single-stranded DNA cleavage.