Comparison between Coacervation Property and Secondary Structure of Synthetic Peptides, Ile-containing Elastin-derived Pentapeptide Repeats

A series of Ile-containing elastin-derived peptide-analogs, (Ile-Pro-Gly-Val-Gly)n (n=7–10) possessing remarkable and reversible coacervation property were newly synthesized. In comparison with the known elastin-derived peptideanalogs, which were so-called polypeptides, the obtained 35 to 50 mer peptides, (IPGVG)n (n=7–10) were significantly low molecular sized-polypeptides. However, they clearly exhibited coacervation property as same as the polypeptides did. Because of their low molecular size, spectrographic analyses of (IPGVG)n (n=7–10) became feasible to carry out. As results of secondary structural analyses by CD and FT-IR, it was found that the coacervation property of the peptides is clearly attributed to the ordered secondary-structures, mainly, type II β–turn. Keywords: CD, coacervation, elastin, FT-IR, secondary structure, type II β–turn.