Glushka John N, Terrell Mark, York William S, O'Neill Malcolm A, Gucwa Angela, Darvill Alan G, Albersheim Peter, Prestegard James H
Complex Carbohydrate Research Center, Department of Chemistry, The University of Georgia, 220 Riverbend Road, Athens, GA 30602-4712, USA.
Carbohydr Res. 2003 Feb 7;338(4):341-52. doi: 10.1016/s0008-6215(02)00461-5.
A 2-O-methylfucosyl-containing heptasaccharide was released from red wine rhamnogalacturonan II (RG-II) by acid hydrolysis of the glycosidic linkage of the aceryl acid residue (AceA) and purified to homogeneity by size-exclusion and high-performance anion-exchange chromatographies. The primary structure of the heptasaccharide was determined by glycosyl-residue and glycosyl-linkage composition analyses, ESIMS, and by 1H and 13C NMR spectroscopy. The NMR data indicated that the pyranose ring of the 2,3-linked L-arabinosyl residue is conformationally flexible. The L-Arap residue was confirmed to be alpha-linked by NMR analysis of a tetraglycosyl-glycerol fragment, [alpha-L-Arap-(1-->4)-beta-D-Galp-(1-->2)-alpha-L-AcefA-(1-->3)-beta-L-Rhap-(1-->3)-Gro], generated by Smith degradation of RG-II. Our data together with the results of a previous study,(1) establish that the 2-O-Me Fuc-containing nonasaccharide side chain of wine RG-II has the structure (Api [triple bond] apiose): [see structure]. Data are presented to show that in Arabidopsis RG-II the predominant 2-O-MeFuc-containing side chain is a mono-O-acetylated heptasaccharide that lacks the non-reducing terminal beta-L-Araf and the alpha-L-Rhap residue attached to the O-3 of Arap, both of which are present on the wine nonasaccharide.
通过对乙酰基酸残基（AceA）糖苷键进行酸水解，从红酒鼠李半乳糖醛酸聚糖II（RG-II）中释放出一种含2-O-甲基岩藻糖基的七糖，并通过尺寸排阻色谱和高效阴离子交换色谱将其纯化至同质。通过糖基残基和糖基连接组成分析、电喷雾离子化质谱（ESIMS）以及1H和13C核磁共振光谱确定了该七糖的一级结构。核磁共振数据表明，2,3-连接的L-阿拉伯糖基残基中的吡喃糖环在构象上具有灵活性。通过对由RG-II的史密斯降解产生的四糖基甘油片段[α-L-阿拉伯糖-（1→4）-β-D-半乳糖-（1→2）-α-L-乙酰基阿拉伯糖醛酸-（1→3）-β-L-鼠李糖-（1→3）-甘油]进行核磁共振分析，证实L-阿拉伯糖残基为α-连接。我们的数据与先前一项研究的结果共同确定，葡萄酒RG-II中含2-O-Me Fuc的九糖侧链具有结构（Api [三键] 阿比糖）：[见结构]。所呈现的数据表明，在拟南芥RG-II中，主要的含2-O-MeFuc侧链是一种单O-乙酰化七糖，它缺少非还原末端的β-L-阿拉伯糖和连接在阿拉伯糖O-3上的α-L-鼠李糖残基，而这两个残基都存在于葡萄酒九糖中。
