DNA Polymerase: Structural Homology, Conformational Dynamics, and the Effects of Carcinogenic DNA Adducts

Figure 3

Conformations of a dG-C8-AAF adduct. Native DNA favors the anti  conformation that allows Watson-Crick base pairs to form with the opposing strand while a dG-C8-AAF in the anti  conformation results in a steric clash between the acetyl moiety (circled red) and the ribose. This causes the conformational equilibrium to shift towards the more favorable syn  conformation. dG-C8-AF adducts differ from dG-C8-AAF adducts by having a smaller hydrogen in place of the circled acetyl moiety. This avoids the steric clash and allows both the syn- and anti  conformations to be sampled.