ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The lack of the positive band at around 226 nm in the CD spectra of poly(prolyl-azetidine-2-carbonyl-proline) in trifluoroethanol and of poly(azetidine-2-carbonyl-prolyl-azetidine-2-carboxylic) acid in F3EtOH and water, the hyperchromism of the absorption maximum at about 202 nm, and the extremely small intensity of the Cβ-Pro, Cγ-Pro, and Cβ-Aze signals for the cis peptide bonds in the 13C nmr spectrum of poly(Pro-Aze-Pro) in F3EtOH indicate that both polyproline analogs exist as disordered chains in this solvent, the trans peptide group being maintained. The disordering of the chains is attributed to an increase in the accessible range of ψ due to the reduced dimensions of the square ring of L-azetidine-2-carboxylic acid residue relative to the pyrrolidine ring of proline and to strong interactions of the haloalcohol with the peptide groups of the chains.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.1976.360150702
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