FIGURE 9.

Single turnover unwinding of the 16bp DNA:DNA (A) and RNA:DNA (B) forked duplexes performed in the presence of heparin trap. The plot from Fig. 1F showing the unwinding of the same substrates in the presence of T₅₀ has been overlaid with the unwinding curves obtained in the presence of heparin for direct comparison. The unwinding data were fit using Kintek Explorer (29) to the scheme given in Fig. 1A for single cycle reactions. The dissociation rate constants obtained for the dsDNA duplex and RNA:DNA hybrid in the presence of heparin were 14.6 ± 0.6 and 13.8 ± 1.0 s⁻¹, respectively, compared with 2.8 ± 0.8 and 2.0 ± 0.3 s⁻¹ observed with a T₅₀ protein trap. The errors indicate the standard error of the fit.