Interaction of spectrin or αR4 with Lu(v13) as assessed by surface plasmon resonance assay. Spectrin or GST-αR4 was immobilized onto CM5 sensor chip. Lu(v13) peptide at different concentrations (0, 0.625, 1.25, 2.5, and 5 μM) was injected at 20 μL/min over the surface in a BIAcore 3000 instrument. The figure shows dose-response curves of Lu(v13) binding to immobilized spectrin (A) or to immobilized GST-αR4 (B).