Solution and solid state conformational preferences of a family of cyclic disulphide bridged tetrapeptides

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• 作者：Nadja Berger ; Fee Li ; Bert Mallick ; J. Thomas Brü ; ggemann ; Wolfram Sander and Christian Merten
• 刊名：Biopolymers
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：107
• 期：1
• 页码：28-34
• 全文大小：695K
• ISSN：1097-0282

文摘

A set of cyclic tetrapeptides of the general form cyclo (Boc-Cys-Pro-X-Cys-OMe) with X being L-/D-Ala, L-/D-Val, and L-/D-Trp was synthesized. These peptides serve as model systems for structure elucidation in solution and feature a variety of structural motifs — namely a β-turn with intramolecular hydrogen bonding interactions, cis/trans isomerism, and a disulphide bond. In this work, we performed a comprehensive structural analysis focussing on their β-turn conformational preferences using NMR, VCD, and Raman spectroscopy. Our results provide evidence for a strong influence of a single stereocenter on the structures of the peptides whereas solvent polarity does not significantly affect them. Additionally, the solid state conformational preferences were studied by crystal structure analysis. Overall, a general trend for the conformational preferences of this set of peptides can be concluded from the results of the complementary investigations.