FIGURE 4.
Competitive binding of wtSkzL and SkzLΔK415 to Pg/Pm. A, titrations of the fractional change in fluorescence (ΔF/Fo) of 100 nm [5F]-SkzL as a function of total [Lys]Pg concentration ([[Lys]Pg]o) in the absence (●) and presence of 2000 (○) and 5000 nm (▴) wtSkzL. B, titrations as in A of 100 nm [5F]-SkzL with [Lys]Pg in the absence (●) and presence of 20 μm (○) SkzLΔK415. C, titrations as in A of 100 nm [5F]-SkzL as a function of total FFR-Pm concentration ([FFR-Pm]o) in the absence (●) and presence of 760 (○) and 2000 nm (▴) of wtSkzL. D, titrations as in A of 100 nm [5F]-SkzL with FFR-Pm in the absence (●) and presence of 20 μm (○) SkzLΔK415. Solid lines represent least squares fits of the data by the cubic competitive binding equation with the parameters listed in Table 1. Experiments were performed and the data analyzed as described under “Experimental Procedures.”