ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
α, β-Dehydroamino acids are expected to provide conformational constraint to the peptide backbone. A pentapeptide containing two dehydrophenylalanines (ΔZPhe) separated by one L-amino acid has been synthesized and its solid state conformation determined. The pentapeptide, Boc-Gly-ΔZPhe-Leu-ΔZPhe-Ala-NHCH3, crystallizes from aqueous methanol in the orthorhombic space group P212121. There are four formula units, C35H46N6O7, in a unit cell of dimensions a = 10.155(3), b = 15.175(1), and c = 23.447(2) Å, at room temperature. The structure was solved by direct methods program, SIR88, and refined to a final R = 0.038 based on 3049 reflections with I 〉 2σ(I). All the peptide links are trans and the backbone conformation of the pentapeptide can be described as a 310-helix, with mean φ, ψ values of -65.1° and -22.8° (the value is averaged over the first four residues). There are four intramolecular 4 → 1 type hydrogen bonds characteristic of 310-type helices. In the crystal, the helices are held together by intermolecular N—H…O=C head-to-tail and lateral hydrogen bonding between symmetry related molecules. This mode of packing is similar to the packing motifs observed so often in other oligopeptides that adopt a 310-helical structure. © 1993 John Wiley & Sons, Inc.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360330203
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