Structure of the glycosylphosphatidylinositol membrane anchor glycan of a class-2 variant surface glycoprotein from Trypanosoma brucei
Structure of the glycosylphosphatidylinositol membrane anchor glycan of a class-2 variant surface glycoprotein from Trypanosoma brucei
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DOI：
10.1006/jmbi.1997.1600
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发表时间：
1998-03-27
影响因子：
5.6
通讯作者：
Ferguson, MAJ
中科院分区：
文献类型：
--
作者：
Mehlert, A;Richardson, JM;Ferguson, MAJ
对纯化的糖蛋白进行氟化氢水溶液去磷酸化和亚硝酸脱氨后，分离出布氏锥虫 2 类变异表面糖蛋白 (VSG) 的糖基磷脂酰肌醇 (GPI) 膜锚的中性聚糖部分。通过高 pH 阴离子交换色谱和凝胶过滤对中性聚糖进行分级，并通过一维和二维 NMR、组成分析、甲基化键分析和电喷雾质谱相结合来解析六种主要聚糖结构。这些聚糖与之前描述的 1 类 VSG 的聚糖类似，因为它们含有线性三甘露糖基序列 Man α 1-2Man α 1-6Man 和高达 Gal α 1-2Gal α 1-6(Gal α 1-2)Gal 的复杂 α-半乳糖分支，但大多数还包含附加的半乳糖残基，α 1-2 连接到非还原末端甘露糖残基，大约三分之一含有额外的半乳糖残基，将β1-3连接到中间的甘露糖残基上。 2 类 VSG GPI 聚糖的额外复杂性根据生物合成模型进行讨论，该模型解释了可由同一锥虫克隆在不同 VSG 类别上表达的全部成熟 GPI 结构。 (C) 1998 学术出版社有限公司。
The neutral glycan fraction of the glycosylphosphatidylinositol (GPI) membrane anchor of a class-2 variant surface glycoprotein (VSG) from Trypanosoma brucei was isolated following aqueous hydrogen fluoride dephosphorylation and nitrous acid deamination of the purified glycoprotein. The neutral glycans were fractionated by high-pH anion exchange chromatography and gel-filtration and six major glycan structures were solved by a combination of one and two-dimensional NMR, composition analysis, methylation linkage analysis and electrospray-mass spectrometry. The glycans were similar to those previously described for class-1 VSGs, in that they contained the linear trimannosyl sequence Man alpha 1-2Man alpha 1-6Man and a complex alpha-galactose branch of up to Gal alpha 1-2Gal alpha 1-6(Gal alpha 1-2)Gal, but most also contained an additional galactose residue attached alpha 1-2 to the non-reducing terminal mannose residue and about one-third contained an additional galactose residue attached beta 1-3 to the middle mannose residue. The additional complexity of the class-2 VSG GPI glycans is discussed in terms of a biosynthetic model that explains the full range of mature GPI structures that can be expressed on different VSG classes by the same trypanosome clone. (C) 1998 Academic Press Limited.