Introduction - This script shows the intercalation of actinomycin D into DNA. Scroll down until the text corresponding to the view is visible. (Based on 173.pdb, S. Kamitori & F. Takusagawa, J. Am. Chem.Soc. 116 4154(1994)).
Here is Antinomycin D. It has a phenoxazone ring (magenta) that can interact with the bases in DNA.
Note how the phenoxazone ring disrupts the nornal base stacking (yellow). This leads to unwinding and distortion of the DNA duplex, which in turn leads to inhibition of both DNA and RNA synthesis.