Thermal and dielectric fingerprints of self-assembling elastin peptides derived from exon30

Three elastin peptides derived from a peculiar elastin sequence (exon 30) were investigated by Infra-red spectroscopy (IRTF), differential scanning calorimetry (DSC) and dielectric spectroscopy (DDS) to clarify the relationship between structural organization and physical properties of these peptides in the solid state. If a great majority of elastin derived peptides form organized structures, only few are able to coacervate, and only one, that is encoded by Exon 30, gives rise to an irreversible precipitation into amyloid fibers. The peptides studied in this work are constituted by 17, 18 or 22 amino acids whose sequences are contained in the longer exon 30. They all contain the XGGZG sequence (where X, Z = V, L) previously suspected to be responsible for amyloid formation in elastin peptides. Two of them gave rise to amyloid fibers while the other one was able to coacervate. In this work we attempted to correlate vibrational, thermal and dielectric behavior of these peptides in the solid state with the propensity to lead to reversible or irreversible aggregation in vivo.