Figure 8.

MukB KE,RE variant is defective in the induction of negative supercoils and stabilizing loops in the DNA. A, either wild type or MukB KE,RE was incubated with the nicked DNA substrate, NAD, and E. coli DNA ligase for 30 min at 37 °C. The products were deproteinized and then analyzed by electrophoresis through an agarose gel containing 10 μg/ml chloroquine in both the gel and the running buffer. B, densitometric lane traces of the gels shown in A. C, MukB KE,RE is defective in stabilizing loops in the DNA. The indicated concentrations of either wild type or MukB KE,RE were incubated with the nicked DNA substrate, DNA gyrase, novobiocin, and DNA ligase as described in the legend to Fig. 2A. The order of addition of components is outlined at the top of the gel. B, MukB; N, novobiocin; G, DNA gyrase; L, DNA ligase. Electrophoresis was with 10 μg/ml chloroquine in both the gel and the running buffer. D, densitometric lane traces of the gel shown in C.