ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The synthesis, CD, ir spectroscopic, and conformational studies of a series of bridged cyclic peptides of the general formula, cyclo[NH-(CH2)n-CO-Gly-Pro-Y-Gly] (2a-d, Y = Gly or Ser(OBut), n = 4 or 2) is reported. As indicated by difference nuclear Overhauser enhancement and Fourier transform ir experiments, the tetrapeptide sequence of cyclo[NH-(CH2)4-CO-Gly-Pro-Gly-Gly] (2a) and cyclo[NH-(CH2)2-CO-Gly-Pro-Gly-Gly] (2b) adopts a 1 ← 4 hydrogenbonded type II β-turn conformation in solution, while cyclo[NH-(CH2)4-CO-Gly-Pro-Ser(OBut) -Gly] (2c) features a type I β-turn, fixed by 1 ← 4 and Oγ … NH intramolecular H bonds. In aqueous solution 2a and 2c show class B and class C CD spectra, respectively. This is the first case reported of a typical class C CD pattern in aqueous solution for a conformationally mobile system having a type I β-turn. Based on the comparison of the band intensities of the bridged models with those of linear and cyclic model systems reported earlier, a set of subspectra with reduced band intensities is suggested for use in the CD analysis of the conformation of polypeptides in solution.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360260908
Permalink
