Biosynthesis of lipophosphoglycan from Leishmania donovani: characterization of mannosylphosphate transfer in vitro.
Biosynthesis of lipophosphoglycan from Leishmania donovani: characterization of mannosylphosphate transfer in vitro.
复制标题
杜氏利什曼原虫脂磷酸聚糖的生物合成：体外甘露糖基磷酸转移的表征。
DOI：
10.1016/0003-9861(92)90523-y
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发表时间：
1992
影响因子：
3.9
通讯作者：
Turco,SJ
中科院分区：
文献类型：
--
作者：
Carver,MA;Turco,SJ
脂磷酸聚糖 (LPG) 是杜氏利什曼原虫前鞭毛体的主要表面糖复合物，由重复 PO4-6Gal(β1,4)Manα1 二糖单元的加帽聚合物组成，通过磷酸糖核心与 alyso-1-O-烷基磷脂酰肌醇锚连接。由 LPG 糖脂锚定部分组成的外源受体可刺激无细胞系统中 LPG 重复磷酸化二糖单元的酶促合成。使用外源受体GDP-[3H]Man、[β-32P]GDP-Man和未标记的UDP-Gal作为底物，从L的LPG缺陷突变体制备膜。缺乏内源性受体的 donovanithat 催化双标记甘露糖基磷酸单元并入具有 LPG 化学和色谱特征的产品中。对放射性标记产物的弱酸水解产生的片段的分析表明[3H]甘露糖-1-[32P]PO4已从双标记糖核苷酸转移。这些结果与 L 的重复单元的提议一致。 donovaniLPG 是通过从各自的核苷酸供体交替转移 1-磷酸甘露糖和半乳糖来合成的。
Lipophosphoglycan (LPG) is the major surface glycoconjugate ofLeishmania donovanipromastigotes and is composed of a capped polymer of repeating PO4-6Gal(β1,4)Manα1 disaccharide units linked via a phosphosaccharide core to alyso-1-O-alkylphosphatidylinositol anchor. An exogenous acceptor composed of the glycolipid anchor portion of LPG was shown to stimulate the enzymatic synthesis of the repeating phosphorylated disaccharide units of LPG in a cell-free system. Using the exogenous acceptor, GDP-[3H]Man, [β-32P]GDP-Man, and unlabeled UDP-Gal as substrates, membrane preparations from an LPG-defective mutant ofL. donovanithat lacks endogenous acceptors catalyzed the incorporation of the doubly labeled mannosylphosphate unit into a product that exhibited the chemical and Chromatographic characteristics of LPG. Analysis of fragments generated by mild acid hydrolysis of the radiolabeled product indicated that [3H]mannose-1-[32P]PO4had been transferred from the dual-labeled sugar nucleotide. These results are consistent with the proposal that the repeating units of theL. donovaniLPG are synthesized by the alternating transfer of mannose 1-phosphate and galactose from their respective nucleotide donors.