FIGURE 4.

Capacity of the λ(244–575)-truncated form of DNA pol λ to extend from the nucleotide preceding the AP site is impaired. Experiments were performed with templates shown in Table 1c. The enzymes and the DNA substrates used are indicated at the top. ss stands for template-primer with no oligonucleotides hybridized downstream from the AP site, whereas 4, 6, and 13 indicate the length of gap regions between the AP site and the oligonucleotide hybridized downstream. Assays were carried out as described under “Experimental Procedures.” A, lane 1, no polymerase present. Lane 2, reaction incubated for 5 min with 0.25 pmol of pol λ. Lane 3, reaction incubated for 5 min with 0.25 pmol of pol λ(244–575). Lane 4, reaction incubated for 5 min with 0.25 pmol of pol λ. Lane 5, reaction incubated for 5 min with 0.25 pmol of pol λ(244–575). Lane 6, reaction incubated for 5 min with 0.25 pmol of pol λ. Lane 7, reaction incubated for 5 min with 0.25 pmol of pol λ(244–575). Lane 8, reaction incubated for 5 min with 0.25 pmol of pol λ. Lane 9, reaction incubated for 5 min with 0.25 pmol of pol λ(244–575). The positions of the primer and of the AP site are indicated. B, quantification of the data from A, expressed as percentage of TLS calculated as described under “Experimental Procedures.” Dark gray bar, pol λ. Light gray bar, pol λ(244–575).