Intermolecular interactions around functional groups in crystals: data for modeling the binding of drugs to biological macromolecules.

When a small biologically active molecule enters the body it has the possibility of interacting with one or many of the large variety of macromolecules that are present. This interaction involves a unique complementary fit between the two that depends not only on the shape, but also on the distribution of charges on the surfaces of both [Fischer (1894). Ber. Dtsch. Chem. Ges. 27, 2984-993]. This recognition between two molecules may elicit a biological response and such processes are the subject of biochemical investigations. The question asked here is: what geometrical information on distances and relative orientations of interacting non-bonded functional groups can be found from X-ray crystallographic investigations?