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. 2012 Aug 10;7(8):e40724. doi: 10.1371/journal.pone.0040724

Figure 2. FLLL32 and FLLL62 inhibit STAT3 dimerization in vitro.

Figure 2

(A) Saturation curves for fluorescence polarization assay. Data represent the change in specific binding observed when 4 nM 5-FAM-SpYLPQTV was incubated with increasing concentrations of STAT3 in the presence and absence of 50 µM FLLL32. (B) Scatchard Plot analysis of the binding of 4 nM 5-FAM-SpYLPQTV in the presence and absence of 50 µM FLLL32 over increasing concentrations of STAT3. Specific binding was plotted along the x-axis while the quotient of the specific binding divided by the corresponding concentration of STAT3 was plotted along the y-axis. The slope of each data set is equal to −1/Kd while the x-intercept is equal to Bmax. (C) Hill Plot analysis of the binding of 4 nM 5-FAM-SpYLPQTV in the presence and absence of 50 µM FLLL32 and FLLL62 over increasing concentrations of STAT3. The log of the quotient of the specific binding divided by the difference between the Bmax and specific binding is plotted along the y-axis while the log of the corresponding concentration of STAT3 is plotted along the x-axis. A slope of 1 indicates noncooperativity in binding. A right-handed shift of the plot shows an increase in the Kd.