Fig. 4.
Interaction of the SH2 domain of Grb2 with a tyrosine-phosphorylated δ subunit peptide. A, Raw binding data. Resonance signal (RU) is plotted as a function of time for several concentrations of GST–Grb2 SH2 injected onto the flow cell. Binding of fusion proteins to immobilized phosphorylated (solid line) and nonphosphorylated (broken line) δ subunit peptide is shown. Concentrations of fusion proteins injected were 31.3, 62.5, 125, 250, 500, and 1000 nm. B, Determination of dissociation constant. Extrapolated steady-state binding responses (Req) are plotted versus fusion protein concentration. A dissociation constant (Kd) of 226 nm was estimated by nonlinear regression analysis.