Actinomycin–DNA complex structure. (A) The structure of a complex between a DNA duplex (shown as a space-filling model) and actinomycin B (shown as a ball-and-stick model). Two actinomycin B molecules are bound in the complex. (B) The structure of actinomycin B showing the phenoxazone ring. Notice how the phenoxazone (yellow) slides between base pairs of the DNA. Abbreviation: Me, methyl.
[Drawn from 1I3W.pdb]