ISSN:
0006-3525
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Sample peptides Boc-Leu4-Aib-Leu4-OBzl and Boc-(Leu4-Aib)2-OBzl, were crystallized by the solvent-evaporation method. Both crystals are monoclinic, with space group of P21 and Z = 2. The cell parameters are a = 16.580(7), b = 21.105(7), c = 11.583(4) Å, and β = 104.90(3)° (Boc-Leu4-Aib-Leu4-OBzl), and a = 15.247(9), b = 19.04(l), c = 16.311(9) Å, and β = 117.10(1)° [Boc-(Leu4-Aib)2-OBzl]. Crystal structures were solved by the direct method and refined to R values of 0.096 (the former peptide) and 0.112 (the latter). Peptide backbones fold into a right-handed α-helix, except for the C-terminal Aib residue in Boc-(Leu4-Aib)2-OBzl. Both peptide molecules are stabilized by six (the former) or seven (the latter) intramolecular (5 → 1) hydrogen bonds, and arranged in the head-to-tail fashion, which makes an infinite column. In this column, one (the former) or two (the latter) intermolecular hydrogen bonds link the neighboring molecules. In the case of Boc-Leu4-Aib-Leu4-OBzl, the solvent molecule N, N-dimethylformamide was found in the difference Fourier map. There was a hydrogen bond between peptide and solvent molecule. Along the lateral direction, only hydrophobic contacts were observed between adjacent peptide molecules.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bip.360310807
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