Bossio J C, de Iannino N I, Dankert M A
Biochem Biophys Res Commun. 1986 Jan 14;134(1):205-11. doi: 10.1016/0006-291x(86)90548-6.
EDTA-treated Rhizobium trifolii cells (strain NA30) incorporate radioactivity from (14C) labeled UDP-Clc, UDP-ClcA, Acetyl-Coa and/or phosphoenol pyruvate into chloroform: methanol: water (1:2:0.3) extracts. The incorporation products have properties of prenyl-phospho-sugars; mild alkaline hydrolysis of these extracts produce cyclic phosphate esters suggesting the presence of a diphosphate bridge, and mild acid or catalytic reduction-alkaline phosphatase treatments release four main components a, b, c and d, as judged by paper electrophoresis and chromatography and gel filtration studies. The four components can be obtained (14C)acetyl-labeled, but only compound c and to a lesser degree compound b can be (14C)pyruvate-labeled. For the exopolysaccharide produced by this strain the following repeating unit has been proposed (Robertsen et al. (1981), Plant Physiol. 67, 389-400): (Formula: see text). The results obtained suggest that the octasaccharide repeating unit (compound a) with one (compound b) or two (compound c) ketal pyruvate residues are assembled on a lipid acceptor. All these compounds are assumed to be intermediates in the biosynthesis of R. trifolii exopolysaccharide.
经乙二胺四乙酸（EDTA）处理的三叶草根瘤菌细胞（菌株NA30）能将来自（14C）标记的尿苷二磷酸 - 克莱因酸（UDP - Clc）、尿苷二磷酸 - 克莱因酸A（UDP - ClcA）、乙酰辅酶A和/或磷酸烯醇丙酮酸的放射性掺入氯仿：甲醇：水（1:2:0.3）提取物中。掺入产物具有异戊烯基磷酸糖的特性；这些提取物经温和碱性水解产生环状磷酸酯，表明存在二磷酸桥，经温和酸处理或催化还原 - 碱性磷酸酶处理后，通过纸电泳、色谱和凝胶过滤研究判断会释放出四种主要成分a、b、c和d。这四种成分都可以用（14C）乙酰基标记，但只有化合物c以及程度稍低的化合物b能用（14C）丙酮酸标记。对于该菌株产生的胞外多糖，已提出以下重复单元（罗伯森等人（1981年），《植物生理学》67卷，389 - 400页）：（分子式：见原文）。所得结果表明，具有一个（化合物b）或两个（化合物c）缩酮丙酮酸残基的八糖重复单元（化合物a）是在脂质受体上组装而成的。所有这些化合物都被认为是三叶草根瘤菌胞外多糖生物合成的中间产物。
