Water structure and elastin-like peptide aggregation: A differential calorimetric approach

For the first time, calorimetric studies performed at very low temperature highlighted the preliminary and required conditions for further aggregation/coacervation of peptides from elastin in solution through the structural water reorganization around the peptides. For this purpose, we firstly characterized by turbidimetry and differential scanning calorimetry the synthetic S4 fragment peptide containing the XGGZG motif (where X and Z correspond to Valine or Leucine) which is able to form amyloid fibres under certain conditions. We also investigated two medium-sized elastin-related model elastin peptides containing the VGVPG motif (E50 and E18) as well as their analogues where proline is hydroxylated in hydroxyproline. These peptides were shown to coacervate, and a close correlation was found between the inverse transition temperature obtained by turbidimetry and the clathrate-like structures evidenced at low temperature by the calorimetric method.