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 200 nM αVβ1, 50 nM αVβ3, 50 nM αVβ5 or 100 nM α5β1. (e-f) Competition of 10 nM FITC-proTGFβ3 peptide binding to 10 nM αVβ6 or 200 nM αVβ8. Competitive antibody-binding curves were globally fitted³⁰ 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.