Biophysical Studies of the InducedDimerization of Human VEGF Receptor 1Binding Domain by Divalent MetalsCompeting with VEGF-A

Angiogenesis is tightly regulated through the binding of vascular endothelial growth factors (VEGFs) to their receptors (VEGFRs). In this context, we showed that human VEGFR1 domain 2 crystallizes in the presence of Zn 2+ , Co 2+ or Cu 2+ as a dimer that forms via metal- ion interactions and interlocked hydrophobic surfaces. SAXS, NMR and size exclusion chro- matography analyses confirm the formation of this dimer in solution in the presence of Co 2+ , Cd 2+ or Cu 2+ . Since the metal-induced dimerization masks the VEGFs binding surface, we investigated the ability of metal ions to displace the VEGF-A binding to hVEGFR1: using a competition assay, we evidenced that the metals displaced the VEGF-A binding to hVEGFR1 extracellular domain binding at micromolar level.