In vitro synthesis of a lipid-linked acetylated and pyruvilated olicosaccharide in Rhizobium trifolii
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...
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| Autores principales: | , , |
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_0006291X_v134_n1_p205_Bossio |
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| Sumario: | 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 componenets 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): {A figure is presented}. 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. © 1986. |
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