Figure 5.

Probing of thymine unpairing in DNA by KMnO₄. (a) Nontemplate strand. (b) Template strand. WT, DNA containing no 2-AP. Numbers on the top indicate the positions of 2-AP in DNA. RNAP, RNA polymerase. pSA852 is supercoiled plasmid DNA. The positions of each KMnO₄-reacted unpaired thymine are indicated by the numbers on the right with arrows. DNA sequencing ladders for A, T, G, and C were generated by using the DNA sequencing kit (BRL). The DNA template used in sequencing was the 358-bp PCR DNA fragment containing 2-AP at −11 position; the results show that the complementary base for 2-AP after amplification is T.