Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
J Phys Chem A. 2010 Mar 18;114(10):3457-65. doi: 10.1021/jp909899w.
The conversion of soluble proteins to insoluble amyloid fibrils is associated with numerous human diseases. The peptide GNNQQNY is a short segment of the yeast prion protein Sup35 that previously has been found to form amyloid fibrils in a similar manner to the protein itself. The approach taken in this work was to attach this peptide sequence to an insoluble polymer matrix through solid phase peptide synthesis and give it the internal freedom to fold into its local conformation in an organic solvent. Observation of its monomeric structure, free from the effects of aggregation, entropic solvent effects, and neighboring molecules, was possible by two-dimensional high-resolution magic angle spinning (1)H NMR spectroscopy. Analysis of the through-bond correlations and through-space interactions observed in the spectra, combined with global energy minimization via computational studies, led to the observation that the peptide chain adopts a compact beta-like turn at the central hydrophilic residues. The technique of peptide attachment to a polymer resin and observation by NMR may allow for future study of single peptide fragments prone to aggregation.
可溶性蛋白质转化为不溶性淀粉样纤维与许多人类疾病有关。肽 GNNQQNY 是酵母朊病毒 Sup35 的一个短片段，以前被发现以类似于蛋白质本身的方式形成淀粉样纤维。这项工作采用的方法是通过固相肽合成将该肽序列连接到不溶性聚合物基质上，并赋予其在有机溶剂中折叠成局部构象的内部自由度。通过二维高分辨率魔角旋转 (1)H NMR 光谱可以观察到其单体结构，不受聚集、熵溶剂效应和相邻分子的影响。通过分析谱图中观察到的键间相关和空间相互作用，并结合通过计算研究进行的全局能量最小化，观察到肽链在中心亲水残基处采用紧凑的β样转角。通过 NMR 观察将肽连接到聚合物树脂上的技术可能允许对易于聚集的单个肽片段进行未来研究。
