Fig. 6.

Reactions in trans. The reactions contained, in reaction buffer at 50 °C, 5 nM [³H]pGB1/S1 (initially 90–95% SC monomer), 1.5 nM enzyme ((a) wt SfiI; (b)Y68F) and either 25 nM HEX-21 (filled circles) or no oligoduplex (open circles). [HEX-21 is a specific duplex for SfiI; Table 1.] Reactions were carried out and analysed as in Figure 4 to determine the residual concentrations of the SC DNA substrate.