Figure 7.

Crystal structure of an hPolη•DNA insertion-stage complex. The polymerase active site (A) viewed from the major groove side of the DNA template–primer duplex and (B) rotated around the horizonal axis by 90°, viewed from the ceiling and along the base stack. Carbon atoms of hPol $\mathrm{\eta }$, template, primer, and the 6-oxo-M₁dG residue are colored in tan, light blue, pink, and golden rod, respectively. Selected residues and atoms are labeled, H-bonds are thin solid lines, and water molecules are small red spheres. The structure of the complex did not reveal an incoming dCTP, and the nucleotide depicted in ball-and-stick mode is from the superimposed structure of the extension-stage complex to demonstrate a clash between incoming residue and the adduct in an anti-conformation. Two glycerol molecules located in the vicinity of the active site are shown with carbon atoms colored in magenta.