ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A series of peptides, Trp-(Pro)n-Tyr, n = 0,…,5 were synthesized. Details of the synthetic method using the Merrifield method are given. The initial objective was to determine the characteristic distance R0 for energy transfer from tyrosine to tryptophan. This objective became submerged in the question of the structure of the chain of prolyl spacers. The efficiency of the energy transfer diminishes as the number of intervening prolines increases. Quantitatively the fit is much better if we assume that the peptides have a polyproline I structure (cis) than if we assume a trans polyproline II structure. Proton nmr spectra on the other hand suggest that the n = 1,3,5 peptides are mixtures of rotamers. Our conclusions are similar to those of previous workers, i.e., that in water there is a transition from a mixture of structures for small n to an all-trans structure at some n 〉 5. This means that in water, at least, proline is a dubious spacer for energy-transfer studies.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1977.360160205
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