Taniguchi Tohru, Tone Ikuko, Monde Kenji
Laboratory of Advanced Chemical Biology, Graduate School of Advanced Life Science, Frontier Research Center for Post-Genome Science and Technology, Hokkaido University, Kita-ku, Sapporo 001-0021, Japan.
Chirality. 2008 Mar;20(3-4):446-53. doi: 10.1002/chir.20465.
Application of vibrational circular dichroism (VCD) spectroscopy to structural analysis of carbohydrates has recently progressed. However, few studies on glycoconjugates VCD have thus far been reported, despite the fact that naturally occurring carbohydrates exist as various glycoconjugates. To further explore the application of the VCD technique, we have measured a series of aromatic glycosides and found that axial aromatic glycosides exhibited a negative band at around 1230 cm(-1) while equatorial ones showed flat features in this region. This is the first structure-spectra relationship on glycoconjugate VCD that distinguishes the stereochemistry of the sugar anomers. Several model compounds were prepared and their vibrational properties calculated by using the density functional theory (DFT) method, which assigned the vibrational mode of this band based on the stretching motion of the glycosidic oxygen and aromatic carbon. This concept that aglycan parts can reflect stereochemical information of sugar moieties may encourage further VCD studies on glycoconjugates to realize practical structural analysis of carbohydrates.
振动圆二色性（VCD）光谱在碳水化合物结构分析中的应用近来取得了进展。然而，尽管天然存在的碳水化合物以各种糖缀合物的形式存在，但迄今为止关于糖缀合物VCD的研究报道很少。为了进一步探索VCD技术的应用，我们测量了一系列芳香糖苷，发现轴向芳香糖苷在约1230 cm⁻¹处呈现一个负峰，而赤道芳香糖苷在此区域呈现平坦特征。这是糖缀合物VCD中第一个区分糖异头物立体化学的结构 - 光谱关系。制备了几种模型化合物，并使用密度泛函理论（DFT）方法计算了它们的振动性质，该方法基于糖苷氧和芳香碳的伸缩运动确定了该峰的振动模式。糖苷配基部分能够反映糖部分立体化学信息的这一概念可能会促进对糖缀合物的进一步VCD研究，以实现碳水化合物的实际结构分析。
