Solution and Solid-State Models of Peptide CH···O Hydrogen Bonds
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- 作者：Paul W. Baures ; Alicia M. Beatty ; Muthu Dhanasekaran ; Brian A. Helfrich ; Waleska Pé ; rez-Segarra ; and John Desper
- 刊名：Journal of the American Chemical Society
- 出版年：2002
- 出版时间：September 25, 2002
- 年：2002
- 卷：124
- 期：38
- 页码：11315 - 11323
- 全文大小：166K
- 年卷期：v.124,no.38(September 25, 2002)
- ISSN：1520-5126
文摘
Fumaramide derivatives were analyzed in solution by 1H NMR spectroscopy and in the solidstate by X-ray crystallography in order to characterize the formation of CH···O interactions under eachcondition and to thereby serve as models for these interactions in peptide and protein structure. Solutionsof fumaramides at 10 mM in CDCl3 were titrated with DMSO-d6, resulting in chemical shifts that moveddownfield for the CH groups thought to participate in CH···O=S(CD3)2 hydrogen bonds concurrent withNH···O=S(CD3)2 hydrogen bonding. In this model, nonparticipating CH groups under the same conditionsshowed no significant change in chemical shifts between 0.0 and 1.0 M DMSO-d6 and then moved upfieldat higher DMSO-d6 concentrations. At concentrations above 1.0 M DMSO-d6, the directed CH···O=S(CD3)2hydrogen bonds provide protection from random DMSO-d6 contact and prevent the chemical shifts forparticipating CH groups from moving upfield beyond the original value observed in CDCl3. X-ray crystalstructures identified CH···O=C hydrogen bonds alongside intermolecular NH···O=C hydrogen bonding, aresult that supports the solution 1H NMR spectroscopy results. The solution and solid-state data thereforeboth provide evidence for the presence of CH···O hydrogen bonds formed concurrent with NH···O hydrogenbonding in these structures. The CH···O=C hydrogen bonds in the X-ray crystal structures are similar tothose described for antiparallel 
-sheet structure observed in protein X-ray crystal structures.
-sheet structure observed in protein X-ray crystal structures.