ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The x-ray diffraction study of the C-terminally unprotected tripeptide benzyloxycarbonyl-L-alanyl-α-aminoisobutyl-α-aminoisobutylic acid (Z-L-Ala-Aib-Aib-OH) has shown that the molecule adopts a consecutive type III β-turn, which characterizes a right-handed 310 helix. A very weak 4 → 1 intramolecular hydrogen bond with the long N-O distance of 3.32 Å, and a unique “oxy analogue” of the 4 → 1 hydrogen bond with the O-O distance of 2.77 Å, were observed. The stability of the observed conformation with the asymmetric Aib residues was theoretically evaluated by a conformation-energy calculation. The stereochemical characteristics of Aib and Ala residues were made clear by a comparison of the conformations of the short peptides containing both Aib and Ala residues.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360290616
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