Figure 7. Analysis of PhrB DNA binding and bending in vitro.
A. Fluorescence anisotropy of PhrB plotted at increasing protein concentrations per amount of 30 bp dsDNA oligonucleotide substrate (o30dsDNA). Error bars represent the standard error of the mean for 3 independent experiments with a total of 6 replicates. B. Fluorescence anisotropy of PhrB plotted at increasing protein concentrations per amount of UV irradiated (1000 joules/m2) o30dsDNA oligonucleotide substrate. Error bars represent the standard error of the mean for 3 independent experiments with a total of 6 replicates. C. Protein duplex DNA bending assay. Shown is a (2.5 μg/ml) chloroquine gel of plasmid DNA (pCRBlunt2bp) incubated with topoisomerase I, DNA gyrase with or without the addition of topoisomerase I, and increasing concentrations of PhrB to DNA (1:1, 10:1, 100:1) with or without the addition of topoisomerase I. The direction of migration of less negatively supercoiled DNA (+) and more negatively supercoiled DNA (−) is indicated.
