Figure 6.

Template recognition requires the cryptic 5′-GA'-3 pair. The identity of the ‘cryptic’ guanosine or adenine in the 5′-GA'-3 pair is necessary for oligoribonucleotide synthesis. Oligoribonucleotide synthesis decreases when the cryptic adenine (lanes 1–12) or guanosine (lanes 17–28) of the 5′GA'3 pair are modified with any other deoxynucleotide. Products were independently labeled with all four radioactive ribonucleotides. A control experiment with the canonical 5′-GA'-3 pair (lanes 13–16) is present and the identity of the oligoribonucleotide products are indicated.