Bioactive peptides: Conformational studies of [TYR4] cyclolinopeptide A

The solid state conformational analysis of [Tyr4] cyclolinopeptide A has been carried out by x-ray diffraction studies. The crystal structure of the monoclinic form, grown from a dioxane-water mixture [a = 9.849 (5) Å, b = 20.752 (4) Å, c = 16.728 (5) Å, β = 98.83 (3)°, space group P21, Z = 2], show...
Ausführliche Beschreibung

The solid state conformational analysis of [Tyr4] cyclolinopeptide A has been carried out by x-ray diffraction studies. The crystal structure of the monoclinic form, grown from a dioxane-water mixture [a = 9.849 (5) Å, b = 20.752 (4) Å, c = 16.728 (5) Å, β = 98.83 (3)°, space group P21, Z = 2], shows the presence of five intramolecular N-H- O=C hydrogen bonds, with formation of one C17 ring structure, one α-turn (C13), one inverse γ-turn (C7), and two β-turns (C10, one of type III and one of type 1). The Pro1-Pro2 peptide unit is cis (ω = 5°) all others are trans. The structure is almost superimposable with that of cyclolinopeptide A. The rms deviation for the atoms of the backbones is on the average 0.33 Å. © 1995 John Wiley & Sons, Inc. Ausführliche Beschreibung