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

Figure 5

Mechanism for bypass of a dG-C8-AAF adduct in the NarI sequence. A polymerase more suited for incorporation across from the adduct places a proper dCTP:G base pair at the adducted position followed by incorporation, then dissociation of the enzyme. A subsequent rearrangement of the DNA to form a 2 nucleotide budge ensues, allowing a possible second polymerase to perform extension from this slipped structure, resulting in a −2 deletion frameshift product.