Elastic Protein-Based Polymers a Step Towards Plasticity: Thermal Stability of Glu-Containing Co-Polypeptides as Analyzed by Differential Scanning Calorimetry

Plastic protein-based polymers with the same conformational potential, but with different degree of thermal stability have been synthesized and thermally characterized by differential scanning calorimetry to provide the conception of behavior of thermoplasticity. Dramatic increase in the temperature between melting and decomposition transitions has been observed, upon inclusion of glutamic acid residue into the hydrophobic sequence of FVGVP. Glu-containing co-polymers of IVGVP showed a markedly different behavior by exhibiting exothermic crystallization transition before melting shows the typical thermoplasticity. Secondary structure in trifluoroethanol for all the polymers show, a well behaved α-helix as evident from the circular dichroism studies, in association with a significant amount of random structure contributes to extended stability.