Figure 4

PriB stimulates the helicase activity of PriA. A) Unwinding of 1 nM Fork 3 by 2 nM PriA in the presence of N. gonorrhoeae PriB (circles) or E. coli PriB (triangles). Measurements are reported in triplicate and error bars represent one standard deviation of the mean. B) Unwinding of 1 nM forked DNA substrates by 2 nM PriA in the presence or absence of 100 nM N. gonorrhoeae PriB (as monomers). The inset shows the structure of the DNA substrates, where n equals the length of the fluorescein-labeled lagging strand arm. Measurements are reported in triplicate and error bars represent one standard deviation of the mean.