McConville M J, Bacic A
Walter and Eliza Hall Institute of Medical Research, Melbourne, Australia.
J Biol Chem. 1989 Jan 15;264(2):757-66.
The glycolipids of the protozoan Leishmania major strain LRC-L119 belong to a class of glycoinositol phospholipids (GIPL) that show partial structural homology to the phosphatidylinositol-containing glycolipid membrane anchors of several eukaryotic proteins and the lipid moiety of L. major lipophosphoglycan. The GIPLs were the only glycolipids detected and were purified by octyl-Sepharose and thin layer chromatographies. Analysis of the native and dephosphorylated glycolipids (GIPLs 1-6) by gas chromatography-mass spectrometry revealed that the glycan moieties have between 4 and 10 saccharide residues and all contain mannose, galactose, and non-N-acetylated glucosamine. Some of the GIPLs also contain glucose (GIPL-6) and hexose monophosphate residues (GIPL 4-6). The presence of an inositol phospholipid moiety in all the GIPLs is indicated by the identification of 1 myo-inositol monophosphate residue/molecule and their susceptibility to phosphatidylinositol-specific phospholipase C. However, heterogeneity in the lipid moieties is indicated by differences in the compositional analysis and the behavior of the GIPLs on the thin layer chromatography after mild alkali hydrolysis or phospholipase A2 treatment. These results demonstrate that GIPLs 1-4 contain 1-alkyl-2-acylglycerol composed of saturated unbranched alkyl chains with carbon chain lengths of 18-26 and acyl chains of myristate, palmitate and stearate, whereas GIPL-5 and -6 contain lyso-alkylglycerol composed of mainly C24:0 and C26:0 alkyl chains. Analysis of the products of nitrous acid deamination demonstrates that these glycerolipids are present as alkylacylphosphatidylinositol (GIPLs 1-4) and 1-O-alkylglycerophosphoinositol (GIPL-5 and -6), respectively. GIPL-2 and -3 are labeled on the surface of living promastigotes with galactose oxidase/NaB[3H]4. These GIPLs also react with three monoclonal antibodies that recognize the surface of promastigotes and amastigotes of L. major and other Leishmania spp.
利什曼原虫主要菌株LRC-L119的糖脂属于一类糖基肌醇磷脂（GIPL），它们与几种真核蛋白含磷脂酰肌醇的糖脂膜锚以及利什曼原虫脂磷壁酸的脂质部分具有部分结构同源性。GIPL是唯一检测到的糖脂，通过辛基琼脂糖和薄层色谱法进行纯化。通过气相色谱-质谱法对天然和去磷酸化的糖脂（GIPL 1-6）进行分析，结果显示聚糖部分含有4至10个糖残基，且均含有甘露糖、半乳糖和非N-乙酰化葡糖胺。部分GIPL还含有葡萄糖（GIPL-6）和己糖单磷酸残基（GIPL 4-6）。所有GIPL中均存在肌醇磷脂部分，这通过鉴定每个分子有1个肌醇单磷酸残基以及它们对磷脂酰肌醇特异性磷脂酶C的敏感性得以表明。然而，脂质部分的异质性通过组成分析的差异以及温和碱水解或磷脂酶A2处理后GIPL在薄层色谱上的行为得以体现。这些结果表明，GIPL 1-4含有由碳链长度为18-26的饱和无支链烷基链以及肉豆蔻酸、棕榈酸和硬脂酸的酰基链组成的1-烷基-2-酰基甘油，而GIPL-5和-6含有主要由C24:0和C26:0烷基链组成的溶血烷基甘油。亚硝酸脱氨产物分析表明，这些甘油脂分别以烷基酰基磷脂酰肌醇（GIPL 1-4）和1-O-烷基甘油磷酸肌醇（GIPL-5和-6）的形式存在。GIPL-2和-3在活的前鞭毛体表面被半乳糖氧化酶/NaB[3H]4标记。这些GIPL还与三种单克隆抗体发生反应，这三种单克隆抗体可识别利什曼原虫主要菌株以及其他利什曼原虫属前鞭毛体和无鞭毛体的表面。
