ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The thermal triple helix-coil transition of covalently bridged collagenlike peptides with repeating sequences of (Ala-Gly-Pro)n, n = 5-15, was studied optically. The peptides were soluble in water/acetic acid (99:1) and were found to form triple-helical structures in this solvent system beginning with n = 8. The thermodynamic analysis of the transition equilibrium curves for n = 9-13 yielded the parameters ΔH°s = -7.0 kJ per tripeptide unit, ΔS°s = -23.1 J deg-1 mol-1 per tripeptide unit for the coil-to-helix transition, and the apparent nucleation parameter σ ≃ 5 × 10-2. It was suggested through double-jump temperature experiments that the rate-limiting step during refolding is not only influenced by the difficulties of nucleation, but also by cis-trans isomerization of the Gly-Pro peptide bond.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1980.360191017
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