Figure 4.

Binding affinities calculated from competition by RGD-mimetic antibodies of ectodomain binding to fluorescent RGD peptides using fluorescence polarization. (A–D) Competition of 10 nM FITC-cyclic-ACRGDGWCG binding to 200nM αVβ1, 50nM αVβ3, 50nM αVβ5 or 100nM α5β1. (E–F) Competition of 10nM FITC-proTGFβ3 peptide binding to 10nM αVβ6 or 200nM αVβ8. Competitive antibody binding curves were globally fitted²⁶ with the maximum FP value in the absence of antibody and the minimum FP value as global fitting parameters, and K_D value for each antibody as individual fitting parameter (Methods). A reliable fit could not be obtained for the α5β1 minibinder and its EC₅₀ value was calculated by fitting the curve with a three-parameter dose-response curve. Means and standard errors are from nonlinear least square fits.