FIGURE 7.

Relationship of the volume of adduct at the guanine N2 and O6 atoms with catalytic efficiency (k_cat/K_m) for dCTP incorporation opposite N²-G and O⁶-G adducts by human Y family polymerases. The molecular volumes (ų) of adducts at the guanine N2 or O6 atom were calculated using the program Chem3D (version 7.0) based on the Connolly surface algorithm (56) and plotted against k_cat/K_m values (Table 2) for dCTP incorporation for various N²-G adducts (▪) and O⁶-G adducts (▴) by four Y family DNA polymerases. The k_cat/K_m values for pol η, pol ι, and pol κ were adapted from previous reports from this laboratory (20–23). A, REV1; B, pol ι; C, pol η; D, pol κ.