Figure 2. Determination of K_B. A.

Scheme of assay, R represents RNAP, P represents promoter fragment and RP_c represents closed complex. B Promoter fragments were incubated with different RNAP concentrations for 20 min and the complexes formed were resolved using 4% native-PAGE. C The amount of radioactivity in bound and free fragments was measured by densitometry and indicated as RP_c and P respectively. RP_c/RP_c+P ratios were plotted as function of RNAP concentrations. K_B was calculated from the slope of the graph. The values obtained are mean of three independent experiments (Table 1).