Figure 3.
Effect of UmuD′2C on nucleotide misincorporation and mismatch extension on lesion-containing and normal DNA templates. Standard standing-start polymerization reactions were carried out by using pol III core, pol II, or UmuD′2C. (A) Reactions carried out by using a DNA template containing an abasic lesion, X. (B) Reactions carried out by using a natural DNA template in which X is replaced by T. The lanes labeled as G, A, T, and C denote reactions carried out with a single dNTP substrate, dGTP, dATP, dTTP, and dCTP, respectively. The lanes labeled as 4 and 0 denote reactions carried out in the presence and absence of four dNTPs, respectively. Lane P contains the 32P-labeled primer in the absence of proteins. The abasic lesion containing and natural DNA templates are shown above each gel. A portion of each template sequence is shown on the right. UmuD′2C measurements made in the presence of pol III (1 nM) and pol II (0.2 nM), resulted in banding patterns identical to those shown in the UmuD′2C panel.