Figure 9. Conformational Transitions of Dpo4 and oxoG-Modified Template-Primer DNA Associated with Nucleotide Binding and Covalent Incorporation Steps Following Superimposition of Dpo4 Palm and Finger Domains.

(A) Overall comparative views (following superimposition of Dpo4 palm and finger domains) of the structures of the preinsertion binary complex (in silver) and the insertion ternary complex with incoming dCTP (in color). The DNA-backbone phosphate groups in contact with the Dpo4 little-finger and thumb domains are shown as spheres. Upon dCTP binding, DNA slides one step along the little-finger domain, and the oxoG residue of the template strand of the insertion ternary complex takes the place of C7 in the preinsertion binary complex.

(B) Overall comparative views (following superimposition of Dpo4 palm and finger domains) of the structures of the insertion ternary complex with incoming dCTP (in color) with the postinsertion binary complex after covalent cytosine incorporation (in beige).