FIG 8 .

Inhibition of SinR variants at different SinI concentrations. SinI was titrated against SinR variants prebound to the native operator site in order to analyze the ability of SinR proteins to bind to the antagonist SinI. Fluorescently labeled DNA (10 nM concentration) was preincubated with 5 µM of SinR, followed by a SinI titration and the measurement of fluorescence polarization. The polarization data at various SinI concentrations have been normalized to represent the percentages of DNA bound to SinR based on the measured levels of polarization of both free DNA and the DNA:SinR complex; for all of the SinR proteins, the DNA binding is saturated at 5 µM SinR and 10 nM DNA. The bars show the mean values and standard deviations of three measurements.