The B4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine residues alpha-linked to serine or threonine residues in cell surface glycoproteins.
The B4 lectin from Vicia villosa seeds interacts with N-acetylgalactosamine residues alpha-linked to serine or threonine residues in cell surface glycoproteins.
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DOI：
10.1016/s0021-9258(18)32554-7
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发表时间：
1983-04
期刊：
影响因子：
--
通讯作者：
S. Tollefsen;R. Kornfeld
中科院分区：
文献类型：
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作者：
S. Tollefsen;R. Kornfeld
我们研究了簇毛蚕豆种子中B4凝集素的碳水化合物结合特性。B4凝集素特异性地凝集暴露于TN的红细胞，并与这些红细胞结合(1.4×10(6)位/细胞)，结合常数为4.2×10(7)M-1。测定了能使B4凝集素与TN暴露的红细胞结合抑制50%的糖和糖肽的浓度。N-乙酰半乳糖胺是最好的单糖抑制剂，当浓度为0.04 mM时，其结合抑制率为50%。其他单糖按效力递减的顺序抑制凝集素结合：N-乙酰半乳糖胺大于甲基-α-半乳糖苷大于对硝基苯基-α-半乳糖苷或β-半乳糖苷大于甲基-β-半乳糖苷，半乳糖大于半乳糖胺大于甘露糖，N-乙酰氨基葡萄糖。二糖Galβ1，3GalNAc在2.8 mM的浓度下对结合有50%的抑制作用，该浓度与对硝基苯基-α-或β-半乳糖苷的浓度相似。含有O-糖基连接的寡糖单元的糖肽比单独的寡糖单元对凝集素结合的抑制作用明显更强。最有效的糖肽抑制剂是一种胎球蛋白糖肽，含有两个α-连接的N-乙酰半乳糖胺单元。该糖肽在浓度为0.00034 mM时对凝集素结合的抑制率为50%，可能与TN暴露的红细胞上的B4凝集素结合部位非常相似。
We have examined the carbohydrate binding specificity of the B4 lectin from Vicia villosa seeds. The B4 lectin agglutinates Tn-exposed erythrocytes specifically and binds to these erythrocytes (1.4 X 10(6) sites/cell) with an association constant of 4.2 X 10(7) M-1. The concentrations of saccharides and glycopeptides of defined structure which cause 50% inhibition of B4 lectin binding to Tn-exposed erythrocytes were determined. N-Acetylgalactosamine is the best monosaccharide inhibitor, causing 50% inhibition of binding at a concentration of 0.04 mM. Other monosaccharides inhibit lectin binding in the following order of decreasing potency: N-acetylgalactosamine greater than methyl-alpha-galactopyranoside greater than p-nitrophenyl-alpha- or beta-galactopyranoside greater than methyl-beta-galactopyranoside, galactose greater than galactosamine greater than mannose, N-acetylglucosamine. The disaccharide Gal beta 1,3GalNAc causes 50% inhibition of binding at a concentration of 2.8 mM, a concentration similar to that of the p-nitrophenyl-alpha- or beta-galactopyranosides. Glycopeptides containing O-glycosidically linked oligosaccharide units are significantly more potent inhibitors of lectin binding than the oligosaccharide units alone. The most potent glycopeptide inhibitor is a fetuin glycopeptide containing two alpha-linked N-acetylgalactosamine units. This glycopeptide causes 50% inhibition of lectin binding at a concentration of 0.00034 mM and probably closely resembles the B4 lectin binding site on Tn-exposed erythrocytes.