Figure 2.

5′- and 3′-labeled hairpin substrates incubated with SbcCD in the presence of ATPγS. ∗, the position of the ³²P-label. The SbcCD product is flanked by A/G sequencing ladders. Fragments arising as a result of chemical cleavage at the three guanosines adjacent to the hairpin loop are indicated. (A) 3′-end-labeled hairpin (3′HP78) was incubated with SbcCD in the presence of ATPγS, at 16°C for 30 min, and reaction products were resolved on a polyacrylamide gel (lane b). A/G sequencing ladders of 3′HP78 are shown in lanes a and c. (B) 5′-end-labeled hairpin (5′HP78) was incubated with SbcCD in the presence of ATPγS, at 16°C for 30 min, and reaction products were resolved on a polyacrylamide gel (lane b). ∗, the position of the ³²P-label. A/G sequencing ladders of 5′HP78 are shown in lanes a and c. A one-and-one-half base allowance was made to compensate for the nucleoside eliminated in the sequencing reaction.