Aqueous interfacial driving forces in the folding and assembly of protein (elastin)-based polymers. Differential scanning calorimetry studies

The protein element of interest here is poly[4(VPGVG), (VPGEG)] in which there are, on the average, four Glu residues per 100 residues. The transition seen as chemomechanical transduction in the cross-linked matrix is seen before cross-linking as a transition from a solution at low temperature to aggregation and phase separation on raising the temperature above that of the transition. The more dense viscoelastic phase formed, called the coacervate, is about 400 mg polypeptide/ml (40% peptide, 60% water by weight). In the present report differential scanning calorimetry is used to determine the heats of the transition (heats of coacervation) as a function of pH.