Figure 7.

Identification of the primer extension products obtained in the reaction catalyzed by KF exo^– in the presence of dGTP alone (100 µM), using the L modified template (sequence 1, 0.06 µM). Primer extension reactions were conducted for 30 min at 30°C using 0.01 U KF exo^– with ³²P-labeled 19mers sequence 7 and 6 terminating with G (lane 3) and T (lane 4), respectively. The mobilities of the reaction products were compared with those of authentic samples of the oligonucleotides containing either one additional dGMP (indicated as 20GG, sequence 10 or 20TG, sequence 8; lanes 1 and 6, respectively) or two (indicated as 21GGG, sequence 11 or 21TGG, sequence 9; lanes 2 and 5, respectively).