ISSN:
0025-116X
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
The conformational properties of three series of monodispersed, chemically and optically pure, PEGThe following abbreviations have been used in the text: PEG, poly(ethylene glycol); -NHPEG, “amino-PEG”; -NHPEG-M, “amino-PEG” -monomethyl ether; t-Boc, tert-butyloxycarbonyl; Z, benzyloxycarbonyl; Ala, alanine; Met, methionine; Gly, glycine; Glu, glutamic acid; Pro, proline; OBzl, benzyloxy; OEt, ethoxy; CD, circular dichroism; MeOH, methanol; TFE, 2,2,2-trifluoroethanol; HFIP, 1,1,1,3,3,3-hexafluoro-2-propanol.-bound linear host oligopeptides of the general formula \documentclass{article}\pagestyle{empty}\begin{document}$ t{\rm - Boc\rlap{--} (L - Met\rlap{--} )}_n {\rm NHPEG} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ t{\rm - Boc\rlap{--} (L - X\rlap{--} )}_n {\rm NHPEG - M} $\end{document} [X = Ala, Glu(OBzl)] containing a single guest L-Pro residue at different positions in the main chain have been investigated in aqueous and alcoholic solutions as a function of concentration, temperature, and added salts using CD. The corresponding N-deblocked peptides have also been examined. The incorporation of the L-Pro residue into a host petide chain blocks the extension of the α-helical conformation at the level of the segment containing the guest residue at its N-terminal end. The investigations reveal asymmetric helixnucleation properties of the L-Pro residue as predicted by theory. In β-structure-forming oligopeptides, the insertion of a L-Pro residue results in a significant destabilization of the ordered conformation. Thus, aggregation of peptide chains is less pronounced in these co-oligopeptides.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1981.021820713
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