Figure 10.

Hinge domain fragments interfere with MukB-mediated loop formation in the DNA. A, left panel, MukB was incubated with the nicked DNA substrate for 5 min at 37 °C. Either wild-type or KE,RE hinge domain fragment was then added, and the incubation continued for an additional 30 min. Reaction products were then analyzed by agarose gel electrophoresis. Middle panel, densitometric lane traces of lanes 1–4 of the gel shown in A. Right panel, densitometric lane traces of lanes 1 and 5–7 of the gel shown in A. B, left panel, as in A, except that the concentration of wild-type hinge domain fragment in the reaction was varied. Right panel, densitometric lane traces of the gel shown in the left panel. C, hinge domain fragment does not interfere with MukB-induced supercoiling in the slow-moving protein-DNA complex. MukB and wild-type hinge domain fragment were incubated with the nicked DNA substrate for 5 min at 37 °C. NAD and E. coli DNA ligase were then added, and the products were analyzed as in the legend to Fig. 1B.