Switching the N-Capping Region from all-L to all-D Amino Acids in a VEGF Mimetic Helical Peptide.

The N-capping region of an α-helix is a short N-terminal amino acid stretch that contributes to nucleate and stabilize the helical structure. In the VEGF mimetic helical peptide QK, the N-capping region was previously demonstrated to be a key factor of QK helical folding. In this paper, we explored the effect of the chiral inversion of the N-capping sequence on QK folding, performing conformational analysis in solution by circular dichroism and NMR spectroscopy. The effect of such a modification on QK stability in serum and the proliferative effect were also evaluated.