Figure 6
SPR measurements of CIB2-peptide interaction. (A) Either α7B_M, α7B_Scrb or α7B_C peptides (7.5 µM) were injected over His-CIB2 homogeneously immobilized by His-tag on the chip surface. (B) 30 µM of the same peptides were injected over untagged CIB2 previously immobilized on the surface of a COOH5 chip via amine coupling. (C) Increasing concentrations of α7B_M peptide were injected on His-CIB2 immobilized as in (A). Experimental data (black curves) were fitted to a bivalent analyte kinetic model (red curves). All the experiments were performed using 20 mM HEPES pH 7.5, 150 mM KCl, 1 mM DTT, 1 mM Mg2+, 2 mM Ca2+, 50 µM EDTA, 0.005% Tween as buffer. Two minutes injections were performed using a flow rate of 20 µL min−1, dissociations were followed for 200 seconds. (D) A possible scheme of CIB2-α7B_M interaction compatible with the kinetic model. The interaction of a CIB2 monomer immobilized on the chip (green) with a peptide (orange) can lead to the binding of another CIB2 molecule; all steps are fully reversible.
