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Oblique computer graphics stereo diagram of the complex of netropsin with C-G-C-G-A-A-T-T-C-G-C-G, in a view sighting directly down the minor groove with the drug molecule slotted into it in a crescent curving away from the viewer. This view also illustrates the strong stacking of bases down each strand of a Beta-DNA double helix, in a more striking representation than is obtained from a more conventional view of the Beta helix. Positive print from Ektachrome photo taken directly from graphics terminal. Source: Kopka et al., 1985a.

Stereo pair drawing, photographed off the face of an Evans and Sutherland Multipicture System graphics station, of the difference electron density of the antitumor drug netropsin in its complex with B-DNA. The screen image was photographed onto Ektachrome slide film, and this film then was used as a negative in making a positive print. The framework is a representation in three dimensions of one contour level in the electron density of the drug, and the graphics operator has built a skeleton of the netropsin molecule within this contour cage. This is the first point at which information about the drug was built into the analysis and was the point of departure for further least-squares refinement of the DNA-drug complex. Source: Kopka et al., 1985c.