Mizuochi T, Spellman M W, Larkin M, Solomon J, Basa L J, Feizi T
Section of Glycoconjugate Research, Medical Research Council Clinical Research Centre, Harrow, Middx., U.K.
Biochem J. 1988 Sep 1;254(2):599-603. doi: 10.1042/bj2540599.
The present paper describes the structures of the N-linked oligosaccharides of the human-immunodeficiency-virus (HIV) envelope glycoprotein gp120 (cloned from the HTLV-III B isolate and expressed as a secreted fusion protein after transfection of Chinese-hamster ovary cells), which is known to bind with high affinity to human T4-lymphocytes. Oligosaccharides were released from peptide by hydrazinolysis, fractionated by paper electrophoresis, high-performance lectin-affinity chromatography and Bio-Gel P-4 column chromatography, and their structures determined by sequential exoglycosidase digestions in conjunction with methylation analysis. The glycoprotein was found to be unique in its diversity of oligosaccharide structures. These include high-mannose type and hybrid type, as well as four categories of complex-type chains: mono-, bi-, tri- and tetra-antennary, with or without N-acetyl-lactosamine repeats, and with or without a core-region fucose residue. Among the sialidase-treated oligosaccharides, no less than 29 structures were identified as follows: (formula; see text) where G is galactose, GN is N-acetylglucosamine, M is mannose, F is fucose, and '+/- ' means that residues are present in a proportion of chains. The actual number of oligosaccharide structures is much greater, since before desialylation there was evidence that, among the hybrid and complex-type chains, all but 6% contained sialic acid at the C-3 position of terminal galactose residues, and partially sialylated forms of the bi- and multi-antennary chains were present. Detailed evidence for the proposed oligosaccharide sequences will be published as a supplementary paper [T. Mizuochi, M. W. Spellman, M. Larkin, J. Solomon, L. J. Basa & T. Feizi (1988) Biomed. Chromatogr., in the press].
本文描述了人类免疫缺陷病毒（HIV）包膜糖蛋白gp120的N-连接寡糖的结构（该糖蛋白克隆自HTLV-III B分离株，在中国仓鼠卵巢细胞转染后作为分泌型融合蛋白表达），已知其能与人类T4淋巴细胞高亲和力结合。通过肼解从肽中释放寡糖，经纸电泳、高效凝集素亲和色谱和Bio-Gel P-4柱色谱进行分离，并结合甲基化分析通过顺序外切糖苷酶消化确定其结构。发现该糖蛋白在寡糖结构多样性方面具有独特性。这些结构包括高甘露糖型和杂合型，以及四类复合型链：单天线、双天线、三天线和四天线，有或没有N-乙酰乳糖胺重复，有或没有核心区域岩藻糖残基。在经唾液酸酶处理的寡糖中，鉴定出不少于29种结构如下：（分子式；见正文）其中G为半乳糖，GN为N-乙酰葡糖胺，M为甘露糖，F为岩藻糖，“+/-”表示残基存在于一定比例的链中。寡糖结构的实际数量要多得多，因为在去唾液酸化之前有证据表明，在杂合型和复合型链中，除6%外，所有链在末端半乳糖残基的C-3位置都含有唾液酸，并且存在双天线和多天线链的部分唾液酸化形式。所提出的寡糖序列的详细证据将作为补充论文发表[T. Mizuochi, M. W. Spellman, M. Larkin, J. Solomon, L. J. Basa & T. Feizi (1988) Biomed. Chromatogr.,即将发表]。
