Tryptophan-derived peptides. 1: Crystal structure and solution conformation of Boc-Gly-Trp-Ala-OtBu期刊界 All Journals 搜尽天下杂志传播学术成果专业期刊搜索期刊信息化学术搜索

Tryptophan-derived peptides. 1: Crystal structure and solution conformation of Boc-Gly-Trp-Ala-OtBu

Authors:	Uffe Anthoni Carsten Christophersen Claus Flensburg Mogens H. Jakobsen Jan Jensen Per H. Nielsen

Affiliation:	(1) Chemical Institute, The H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark;(2) Centre for Crystallographic Studies, The H. C. Ørsted Institute, University of Copenhagen, Universitetsparken 5, Copenhagen, Denmark

Abstract:	The solid-state structure of Boc-Gly-Trp-Ala-OBu^t was determined by single-crystal X-ray diffraction analysis. The tripeptide gave crystals belonging to the orthorhombic systemP2₁2₁2₁ and at 122.0(5) K:a=11.0663(12),b=14.107(2),c=17.275(2) Å,V=2697.0(5) Å³Z=4,R(F)=0.0259, andR_w(F)=0.0695. The peptide adopts a type-I-turn in the solid state with a single, rather weak, intramolecular hydrogen bond between the Boc-CO and Ala-NH groups (NO 3.082(1) Å, O 167(1)°). The conformation of the Boc-Gly-Trp-Ala-OBu^t peptide has also been studied by¹H NMR spectroscopy. The solvent and temperature dependencies of NH chemical shifts suggests that this hydrogen bond is broken and that all amide protons are solvent exposed in CDCl₃ and (CD₃)₂SO.

Keywords:	Protected tripeptide solution structure crystal structure X-ray analysis NMR analysis
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