ISSN:
0006-3525
Keywords:
Aib peptides
;
crystal state structure
;
helical peptides
;
peptide helices
;
x-ray crystallography
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The crystal-state preferred conformations of six Nα-blocked pentapeptide esters, each containing four helicogenic, achiral α-aminoisobutyric acid (Aib) residues followed by one chiral L-valine (L-Val) or Cα-methyl-L-valine [(αMe)Val] residue at the C-terminus, have been assessed by x-ray diffraction analysis. In all of the compounds the —(Aib)4— sequence is folded in a regular 310-helical conformation. In the four pentapeptides characterized by the L-(αMe)Val residue two conformationally distinct molecules occur in the asymmetric unit. Conversely, only one molecule is observed in the asymmetric unit of two pentapeptides with the C-terminal L-Val residue. In the L-Val based peptides the helical screw sense of the —(Aib)4— sequence is right-handed, whereas in the L—(αMe)Val— analogues both right- and left-handed helical screw senses concomitantly occur in the two crystallographically independent molecules. © 1998 John Wiley & Sons, Inc. Biopoly 46: 433-443, 1998
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
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