Figure 3.

Enlarged side view of the ActD–ATGCG region (ActD is shown as a ball-and-stick model, and DNA is shown as a skeletal model). The two phenoxazone rings of ActD1 (left) and ActD2 (right) are individually intercalated into the G3pC4 step in A and the G12pC13 step in B, respectively C–E. The detailed conformation showing the stacking interactions in the ActD–DNA complex at various base pair steps of the refined structure. Hydrogen bonds are shown as blue dotted lines. Water is shown as a blue sphere.