Figure 5.

Interactions with the flipped Ura base in the enzyme–substrate complex of TDG^82-308 bound to G·U^F DNA (PDBID: 5HF7; 1.54 Å). TDG residues are in stick format (white with nitrogen blue and oxygen red), the Ura-containing DNA is yellow (with 2′-F colored cyan) and water molecules are red spheres. The 2F_o–F_c electron density map, contoured at 1.0 σ, is shown for the DNA and water molecules, but not the enzyme residues (for clarity). Dashed lines represent hydrogen bonds, with interatomic distances (Å).