Helical peptides from VEGF and Vammin hotspots for modulating the VEGF–VEGFR interaction

The design, synthesis, conformational studies and binding affinity for VEGF receptors of a collection of linear and cyclic peptide analogues of the N-terminal α-helix fragments 13–25 of VEGF and 1–13 of Vammin are described. Linear 13(14)-mer peptides were designed with the help of an AGADIR algorithm and prepared following peptide solid-phase synthetic protocols. Cyclic peptide derivatives were prepared on-resin from linear precursors with conveniently located Glu and Lys residues, by the formation of amide linkages. Conformational analysis, CD and NMR, showed that most synthesized peptides have a clear tendency to be structured as α-helices in solution. Some of the peptides were able to bind a VEGFR-1 receptor with moderate affinity. In addition to the described key residues (Phe17, Tyr21 and Tyr25), Val14 and Val20 seem to be relevant for affinity.