| Abstract: | The polypentapeptide, H(L˙Val1-L˙Pro2-D·Ala3-L˙Val4-Gly5)n Val-OMe which is the D·Ala3 analog of the elastomeric polypentapeptide (PPP) of elastin, (L˙Val1-L˙Pro2-Gly3-L˙Val4-Gly5)n, has been synthesized. Its conformation is compared to that of the PPP and found to be similar with a somewhat stabilized β-turn. The D·Ala3 analog coacervates to form a more cohesive viscoelastic material and the coacervate when cross-linked by γ-irradiation exhibits an approximate doubling of the Young's modulus of elasticity. These results are discussed in connection with other related analogs of the polypentapeptide of elastin, which are non-elastomeric, and found to be consistent with a proposed conformationally based librational entropy mechanism of elasticity. |
