Fig. 4.

NP1-coupled HPLC assay of Tel22 and the U-substituted sequences after 2.5 h UVB irradiation at pH 7.5. (A) Tel22 in 150 mM Na⁺ solution. (B) Tel22 in 150 mM K⁺ solution. (C–E) Tel22-Uⁿ in 150 mM K⁺ solution. The HPLC peaks are labeled n-m, in which n refers to the loop that is substituted by U, and m refers to the order of elution. Peak c could not be assigned. Peaks 1–3 are trinucleotides resulting from adjacent photoproducts, and peaks 4–12 are tetranucleotides resulting from nonadjacent photoproducts.