Matsuda T, Kabat E A, Surolia A
Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
Mol Immunol. 1989 Feb;26(2):189-95. doi: 10.1016/0161-5890(89)90101-6.
The carbohydrate binding specificity of the basic lectin from winged bean (Psophocarpus tetragonolobus) was investigated by quantitative precipitin analysis using blood group A, B, H, Le and I substances and by precipitation inhibition with various mono- and oligosaccharides. The lectin precipitated best with A1 substances and moderately with B and A2 substances, but not with H or Le substances. Inhibition assays of lectin-blood group A1 precipitation demonstration that A substance-derived oligosaccharides having the common structure: D-GalNAc alpha(1----3)D-Gal-(beta 1----3/4) to a D-Glc, were the best inhibitors and about 8 and 4 times more active than D-GalNAc and D-GalNAc alpha(1----3)D-Gal, respectively. A difucosyl A-specific oligosaccharide (A-penta), a monofucosyl (A-tetra) and a non-fucosyl containing (A5II) oligosaccharide, D-GalNAc alpha(1----3)D-Gal beta(1----3)D-GlcNAc, had almost the same reactivity, suggesting that the fucose linked to the sub-terminal D-Gal or to the third sugar. D-GlcNAc, from the non-reducing end made no contribution to the carbohydrate binding. Although a terminal non-reducing D-GalNAc or D-Gal residue was indispensible for binding, the lectin bound not only to these terminal non-reducing galactopyranosyl residues, but also showed increased binding to oligosaccharides in which it was bonded to a sub-terminal D-Gal joined to a D-GlcNAc residue, as in blood group A or B substances. This defines the site, thus far, as complementary to a disaccharide plus the beta linkage to the third sugar (D-Glc or D-GlcNAc) from the non-reducing end. The role of the beta(1----3) or beta(1----4) linkage of the sub-terminal non-reducing D-Gal to the D-GlcNAc requires further study.
通过使用A、B、H、Le和I血型物质进行定量沉淀分析，以及用各种单糖和寡糖进行沉淀抑制，研究了四棱豆（Psophocarpus tetragonolobus）碱性凝集素的碳水化合物结合特异性。该凝集素与A1物质沉淀效果最佳，与B和A2物质沉淀效果中等，但与H或Le物质不发生沉淀。凝集素与A1血型沉淀的抑制试验表明，具有共同结构：D-GalNAcα(1→3)D-Gal-(β1→3/4)至D-Glc的A物质衍生寡糖是最佳抑制剂，其活性分别比D-GalNAc和D-GalNAcα(1→3)D-Gal高约8倍和4倍。一种二岩藻糖基A特异性寡糖（A-五糖）、一种单岩藻糖基（A-四糖）和一种不含岩藻糖的（A5II）寡糖D-GalNAcα(1→3)D-Galβ(1→3)D-GlcNAc具有几乎相同的反应性，表明与次末端D-Gal或第三个糖相连的岩藻糖。来自非还原端的D-GlcNAc对碳水化合物结合没有贡献。虽然末端非还原D-GalNAc或D-Gal残基对于结合是必不可少的，但该凝集素不仅与这些末端非还原吡喃半乳糖基残基结合，而且与其中它与连接到D-GlcNAc残基的次末端D-Gal结合的寡糖的结合也增加，如在A或B血型物质中。到目前为止，这定义了该位点与二糖加上从非还原端到第三个糖（D-Glc或D-GlcNAc）的β键互补。次末端非还原D-Gal与D-GlcNAc的β(1→3)或β(1→4)键的作用需要进一步研究。
