Fig. 8.

The flap loop does not inhibit backtracking. (A) Reaction scheme for TFIIS-stimulated transcript cleavage. The sequence of the nucleic acid scaffold used to reconstitute ECs is shown with the position of the halted A24 EC indicated. (B) A24 complexes made in the presence of ATP and GTP were incubated with apyrase to convert NTPs to NDPs. The ECs were then incubated with TFIIS; aliquots were removed at the times indicated; and the RNA products were separated on a 20% denaturing polyacrylamide gel. The fraction of remaining A24 RNA is plotted as a function of reaction time.