Figure 1.

Classification of the non-hydrogen atoms of the four DNA standard bases according to the type of contacts in DNA-drug complexes. The atoms involved in minor groove contacts are represented in red, the atoms involved in major groove contacts in blue, the atoms involved in backbone contacts in black and the rest of the atoms in green. The contact-influencing region of each atom is shown with equispaced concentric circles with radii ranging from 1 Å to 3.5 Å.