Dolain Christel, Grélard Axelle, Laguerre Michel, Jiang Hua, Maurizot Victor, Huc Ivan
Institut Européen de Chimie et Biologie, Pessac, France.
Chemistry. 2005 Oct 21;11(21):6135-44. doi: 10.1002/chem.200500395.
The unambiguous elucidation of a new folded structure in solution may prove to be a very challenging task. The NMR protocols developed for solving the solution structures of alpha-peptides have been applied to aliphatic beta- and gamma-peptides but are not directly applicable to aromatic oligomers. In particular, the string of spin systems in an aromatic sequence cannot be reconstituted solely from correlations between protons. For aromatic oligomers, it is shown that the assignment of a large part of the 13C NMR spectrum through HMBC and HSQC experiments allows to unambiguously assign proton NMR spectra and in turn to interpret NOE correlations. This has been implemented both with quinoline- and pyridine-derived oligoamide foldamers, and should be applicable to a wide range of oligomers including various combinations of monomers. The NOE correlations allow the unambiguous solution structure elucidation of helical conformations of oligoamides derived from pyridine and quinoline monomers showing that, in these series, the solution structures correspond very well to the structures observed in the solid state.
在溶液中明确阐明一种新的折叠结构可能是一项极具挑战性的任务。为解析α-肽的溶液结构而开发的核磁共振（NMR）方法已应用于脂肪族β-肽和γ-肽，但并不直接适用于芳香族低聚物。特别是，芳香序列中的自旋系统链不能仅通过质子之间的相关性来重构。对于芳香族低聚物，研究表明，通过异核多键相关（HMBC）和异核单量子相干（HSQC）实验对大部分13C NMR谱进行归属，能够明确归属质子NMR谱，进而解释核Overhauser效应（NOE）相关性。这已在喹啉和吡啶衍生的寡酰胺折叠体中得到实现，并且应该适用于包括各种单体组合的广泛低聚物。NOE相关性使得能够明确解析源自吡啶和喹啉单体的寡酰胺螺旋构象的溶液结构，表明在这些系列中，溶液结构与固态中观察到的结构非常吻合。
