Precise Conformational Analysis of Some Polypeptides in the solution and liquid crystalline states by multi-nuclear NMR

证明了固体核磁共振化学位移值是分析多肽在固态、溶液和液晶态构象的基础数据。利用基础数据，利用变温高分辨核磁共振谱，阐明了具有长链烷基侧链的多肽的热致液晶的形成和不形成的来源。此外，根据固体核磁共振化学位移值确定了蛋白质在溶液中的高阶结构，氢键在多肽和蛋白质的稳定构象中起着重要作用。为了研究固体多肽中碳键化学位移的影响，测定了一系列含甘氨酸残基的低聚肽的碳氢化学位移谱，发现随着氢键长度的减小，氨基氢键中碳位的化学位移下移。这一实验发现对于了解氢键的性质是非常有用的。利用~(13)C-核磁共振波谱成功地研究了离子载体等生物相关化合物的构象与生化功能之间的关系。

We have demonstrated that solid state ^<13>C and ^<15>N NMR chemical shift values become fundamental data for analyzing conformation of polypeptides in the solid state, solution state and liquid crystalline state. Using the fundamental data, the origin of the formation and no formation of thermotropic liquid crystals for polypeptides with long akyl side chains has been clarified using variable temperature high resolution NMR spectroscopy. Further, higher-order structure of proteins in solution has been determined on the basis of solid state ^<13>C and ^<15>N NMR chemical shift values.The hydrogen bond plays an important role in forming the stable conformation of polypeptides and proteins. In order to investigate the effect of on the ^<13>C NMR chemical shifts of carbonyl carbons in peptides in the solid state, ^<13>C CP/ MAS NMR spectra were measured for a series of the oligopeptides containing glycine residues of which the crystal structures were already determined by X-ray diffraction We have found that the ^<13>C chemical shifts of the carbonyl carbon in the amide type hydrogen bond form move downfield with a decrease in the hydrogen bond length. This experimental finding is very useful to know the nature of hydrogen bond.The relationship between the conformation and the biochemical function in biologically-related compounds such as ionophores has been successfully studied by ^<13>C-NMR spectroscopy.