Figure 5.

Strand displacement DNA synthesis by T7 DNA polymerase alone on various Tus–Ter fork DNAs. (A) T7 DNA polymerase was preincubated with the preformed replication fork substrate and reacted with 1 mM dNTPs. The DNA forks used here were as follows: non-permissive (NP), GC(6) to AT mutation (C to T), GC(6) to CG mutation (C to G), GC(6) at the junction (C Junction), C Open, C C Bubble and permissive (P). Reactions were quenched at 0, 10, 30, 120, 240, 360, 600, 1800 s and products resolved in sequencing gels. Arrows indicates the first arrest position band corresponding to the arrows on the TerB sequence below. (B) Plot showing ‘% run-off synthesis’ against time, quantified from the sequencing gels in (A). The duplicate sets of experiments are shown in Supplementary Figure S10 and also those conducted at 23°C in Supplementary Figure S9.