Levigne Sébastien V, Ralet Marie-Christine J, Quéméner Bernard C, Pollet Brigitte N-L, Lapierre Catherine, Thibault Jean-François J
Unité de Recherche sur les Polysaccharides, leurs Organisations et Interactions, Institut National de la Recherche Agronomique, boîte postale 71627, 44316, Nantes cedex 03, France.
Plant Physiol. 2004 Mar;134(3):1173-80. doi: 10.1104/pp.103.035311. Epub 2004 Feb 26.
Side chains of sugar beet (Beta vulgaris) pectins, which are mainly composed of arabinose (Ara) and galactose (Gal) residues, are esterified by ferulic acid units. Enzymatic hydrolysis of beet cell walls yielded several feruloylated oligosaccharides, which were separated by hydrophobic interaction chromatography. Two new oligomers were isolated in the fraction eluted by 25:75 (v/v) ethanol:water. An arabinotriose and an arabinotetraose esterified by two ferulic acid residues were obtained, and their structure was elucidated by mass spectrometry. It is shown that feruloyl groups are linked to O-5 of Ara residues, in addition to the known O-2 position. This work establishes for the first time, to our knowledge, that two neighboring Ara units may be esterified by two ferulic acid units. This close proximity may have important biochemical implications.
甜菜(Beta vulgaris)果胶的侧链主要由阿拉伯糖(Ara)和半乳糖(Gal)残基组成,这些侧链被阿魏酸单元酯化。甜菜细胞壁的酶促水解产生了几种阿魏酰化低聚糖,通过疏水相互作用色谱法将它们分离。在由25:75(v/v)乙醇:水洗脱的馏分中分离出两种新的低聚物。得到了一种被两个阿魏酸残基酯化的阿拉伯三糖和一种阿拉伯四糖,并通过质谱法阐明了它们的结构。结果表明,除了已知的O-2位置外,阿魏酰基还与Ara残基的O-5相连。据我们所知,这项工作首次证实两个相邻的Ara单元可能被两个阿魏酸单元酯化。这种紧密相邻可能具有重要的生化意义。