Figure 5.

Complete repair of the mismatched bifurcated model system at a site containing consecutive non-standard DNA bases. A single-stranded DNA both 5′-labeled with fluorescein (F) and 3′-labeled with cyanine 3 (CY) was annealed to equimolar amounts of complementary hairpin-forming DNA. The 5′ thymidine (T) of the single-stranded DNA was mispaired with an isoguanosine (iG) in the hairpin. Repair reactions contained combinations of ligase, polymerase, FEN-1 nuclease and 5-methyl isocytosine triphosphate (iCTP) as indicated above the lanes. Complete repair reaction product, cleavage intermediate, 5′-phosphoryl probe and ligation intermediate adenylated probe (Ad-iG) indicated on the left of the gel were resolved by denaturing PAGE and detected by fluorescence imaging. A mock repair product was synthesized chemically and used as a size marker (M).