ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The conformation of cyclolinopeptide A [cyclo(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val)], a naturally occurring cyclic nonapeptide has been investigated in dimethylsulfoxide solution by 270 MHz 1H-nmr. A complete assignment of all CαH and NH resonances has been accomplished using two-dimensional correlated spectroscopy and nuclear Overhauser effects (NOEs). Analysis of interresidue NOEs and JHNCαH values permit construction of a molecular model for the cyclic peptide backbone. The crude model derived from nmr has been used as a starting point for energy minimization, which yields a refined structure largely compatible with nmr observations. The major features of the conformation of cyclolinopeptide A are a Type VI β-turn centered at Pro(1)-Pro(2), with a cis peptide bond between these residues and a γ-turn (C7) structure centered at Ile(6). Two intramolecular hydrogen bonds Val(9) CO - Phe(3)NH (4 → 1) and Leu(5) CO - Ile(7)NH (3 → 1) are observed in the low-energy conformation. The limited solvent accessibility observed for the Val(9) and Leu(5) NH groups in the nmr studies are rationalized in terms of steric shielding.
Additional Material:
10 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360280204
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