FIGURE 9.

Schematic of the relative orientations of dNMPNPPs and 8-oxoG as well as Arg-61 in the Ci, Ai, and Gi insertion-step hpol η complexes. Arrows indicate the movements of dGMPNPP (brown) and dAMPNPP (lilac) into the minor groove relative to dCMPNPP (light blue), the movements of Arg-61 in the Gi (brown carbons) and Ai (lilac carbons) complexes into the major groove relative to the Ci complex (light blue carbons), and the movement of the 3′-terminal T of the primer in the Gi complex into the major groove relative to the Ai and Ci complexes. The relative movements of the nucleotide triphosphates and Arg-61 in the Gi and Ai complexes result in the loss of stacking between the nucleobase of the incoming dNMPNPP and the guanidino group. The movement of the 3′-terminal T in the Gi complex results in an unfavorable orientation of the 3′-OH for an attack at the α-phosphate group.