ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The peptide N-Boc-L-Gly-dehydro-Phe-NHCH3 was synthesized by the combination of N-Boc-L-Gly-dehydro-Phe azlactone and methylamine. The peptide crystallizes in orthorhombic space group P212121 with a = 5.679(2) Å, b = 16.423(9) Å, c = 19.198(10) Å, V = 1791(2) Å3, Z = 4, dm = 1.212(5) Mg m-3, dc = 1.237(1) Mg m-3. The structure was determined by direct methods using SHELXS 86. The structure was refined by full-matrix least squares procedure to an R value of 0.049 for 1509 observed reflections. The molecular dimensions are, in general, in good agreement with the standard values. The bond angle Cα-Cβ-Cγ in the dehydro-Phe residue is 133.6(5)°. The peptide backbone torsion angles are θ1 = -171.4(4)°, ω0 = 178.2(4)°, φ1 = -57.2(6)°, ψ1 = 141.2(4)°, ω1 = -174.4(4)°, φ2 = 71.5(6)°, ψ2 = 7.2(6)°, and ω2 = -179.8(5)°. These values show that the backbone adopts the β-bend type II conformation. The Boc group has a trans-trans conformation. The side-chain torsion angles in dehydro-Phe are χ2 = 1.6(9)°, χ22,1 = 0.5(9)°, and χ22,2 = 179.8(6)°. The plane of C2α-C2β-C2γ is rotated with respect to the plane of the phenyl ring at 0.5(6)°, which indicates that the atoms of the side chain of the dehydro-Phe residue are essentially coplanar. As a result of the β-bend in the structure, an intramolecular hydrogen bond is formed between the oxygen of the ith residue and the NH of the (i + 3)th residue at a distance of 2.940(5) Å. The crystal structure is stabilized by a network of hydrogen bonds and van der Waals interactions.
Additional Material:
3 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360280709
