Figure 11: Preferential insertion of the individual dNTPs opposite a THF abasic site located on the 5 -terminus (A-27) of an A4 tract by T7 Sequenase. The dNTP concentrations used were 0.005, 0.5, 5, 50 and 500  𝜇 M (for dATP the 500  𝜇 M concentration is not shown). Lanes with no added dNTP and with all dNTPs are included. dATP and dGTP are most efficiently inserted opposite the THF lesion.