ISSN:
1075-2617
Keywords:
circular dichroism
;
FT-IR absorption
;
glycopeptides
;
1H nuclear magnetic resonance
;
oligo-peptides
;
peptide conformation
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Stepwise solution syntheses are described of the homo-oligomers Z-(Thr)n-NHCH3 (n=1-4, I1-4), Z-{[Gal(Ac)4β]Thr}n-NHCH3(n=1-5, II1-5) and Z-[(Galβ)Thr]n-NHCH3 (n=1-5, III1-5). Members of the III1-5 series were obtained by de-acetylation of the corresponding oligomers of the II1-5 series. The conformational preferences of the terminally protected homo-peptides of the three series were investigated by FT-IR absorption spectroscopy both in the solid state and in CDCl3 solution, at various concentrations. Proton NMR measurements in CDCl3 and in DMSO-d6 were also carried out and the effect of temperature variation on the chemical shifts of amide protons was determined in DMSO-d6 (range 298-335 K) and in CDCl3 (range 298-320 K). CD spectra were recorded in water and in TFE. Solubility problems prevented measurements in CDCl3 solution for Z-(Thr)4-NHCH3 and for the entire III1-5 series. The existence of unordered structures in the carbohydrate-free oligomers and of more or less extended, organized structures in the glycosylated derivatives is indicated by the NMR and IR measurements. The sugar moieties apparently show a structure-inducing effect on the peptide chain. ©1998 European Peptide Society and John Wiley & Sons, Ltd.
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource