Rudd Timothy R, Skidmore Mark A, Guimond Scott E, Cosentino Cesare, Torri Giangiacomo, Fernig David G, Lauder Robert M, Guerrini Marco, Yates Edwin A
School of Biological Sciences, University of Liverpool, Liverpool, L69 7ZB, UK.
Glycobiology. 2009 Jan;19(1):52-67. doi: 10.1093/glycob/cwn103. Epub 2008 Oct 2.
Principal component analysis (PCA) is a method of simplifying complex datasets to generate a lower number of parameters, while retaining the essential differences and allowing objective comparison of large numbers of datasets. Glycosaminoglycans (GAGs) are a class of linear sulfated carbohydrates with diverse sequences and consequent complex conformation and structure. Here, PCA is applied to three problems in GAG research: (i) distinguishing origins of heparin preparations, (ii) structural analysis of heparin derivatives, and (iii) classification of chondroitin sulfates (CS). The results revealed the following. (i) PCA of heparin (13)C NMR spectra allowed their origins to be distinguished and structural differences were identified. (ii) Analysis of the information-rich (1)H and (13)C NMR spectra of a series of systematically modified heparin derivatives uncovered underlying properties. These included the presence of interactions between residues, providing evidence that a degree of degeneracy exists in linkage geometry and that a different degree of variability exists for the two types of glycosidic linkage. The relative sensitivity of each position (C or H nucleus) in the disaccharide repeating unit to changes in O-, N-sulfation and N-acetylation was also revealed. (iii) Analysis of the (1)H NMR and CD spectra of a series of CS samples from different origins allowed their structural classification and highlighted the power of employing complementary spectroscopic methods in concert with PCA.
主成分分析（PCA）是一种简化复杂数据集以生成较少参数数量的方法，同时保留基本差异并允许对大量数据集进行客观比较。糖胺聚糖（GAGs）是一类具有不同序列以及相应复杂构象和结构的线性硫酸化碳水化合物。在此，PCA被应用于GAG研究中的三个问题：（i）区分肝素制剂的来源，（ii）肝素衍生物的结构分析，以及（iii）硫酸软骨素（CS）的分类。结果表明如下。（i）肝素的（13）C NMR光谱的PCA能够区分其来源并识别结构差异。（ii）对一系列经过系统修饰的肝素衍生物的富含信息的（1）H和（13）C NMR光谱的分析揭示了潜在特性。这些特性包括残基之间相互作用的存在，这提供了连接几何结构中存在一定程度简并性以及两种糖苷键存在不同程度变异性的证据。还揭示了二糖重复单元中每个位置（C或H核）对O -、N - 硫酸化和N - 乙酰化变化的相对敏感性。（iii）对一系列来自不同来源的CS样品的（1）H NMR和CD光谱的分析实现了它们的结构分类，并突出了将互补光谱方法与PCA协同使用的作用。
