Leibiger H, Kersten B, Albersheim P, Darvill A
Complex Carbohydrate Research Center, University of Georgia, Athens 30602-4712, USA.
Glycobiology. 1998 May;8(5):497-507. doi: 10.1093/glycob/8.5.497.
The oligosaccharide side chains of a human anti-lipopolysaccharide IgM produced by a human-human-mouse heterohybridoma were analyzed at each of its five conserved N-glycosylation sites. This antibody also has a potential sixth N-glycosylation site in the variable region of its heavy chain which is not glycosylated. The oligosaccharides were released by digestion with various endo- and exoglycosidases and analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry and fluorophore-assisted carbohydrate electrophoresis. The antibody has various complex- and hybrid-type oligosaccharide structures at Asn 171, various sialylated complex-type oligosaccharides at Asn 332 and 395, and high-mannose-type oligosaccharides at Asn 402 and 563. Of note is the presence in this human IgM of oligosaccharides containing N-glycolylneuraminic acid and N-acetylneuraminic acid in the ratio of 98:2 as determined using anion-exchange chromatography. Furthermore, we observed oligosaccharide structures containing Gal alpha (1,3)Gal that have not been reported as components of human glycoproteins.
对一株人-人-鼠异种杂交瘤产生的人抗脂多糖IgM的寡糖侧链，在其5个保守的N-糖基化位点逐一进行了分析。该抗体在其重链可变区还有一个潜在的第6个N-糖基化位点，但未发生糖基化。用各种内切和外切糖苷酶消化释放寡糖，并通过基质辅助激光解吸/电离飞行时间质谱和荧光团辅助碳水化合物电泳进行分析。该抗体在Asn 171处具有多种复合型和杂合型寡糖结构，在Asn 332和395处具有多种唾液酸化复合型寡糖，在Asn 402和563处具有高甘露糖型寡糖。值得注意的是，使用阴离子交换色谱法测定，该人IgM中含有N-羟乙酰神经氨酸和N-乙酰神经氨酸的寡糖比例为98:2。此外，我们还观察到含有Galα(1,3)Gal的寡糖结构，尚未见报道其作为人糖蛋白的成分。
