Structure of the major oligosaccharide of cobra venom factor.
Cobra venom factor (CVF), the complement-activating glycoprotein in cobra venom, contains three or possibly four N-linked oligosaccharide chains per molecule and is devoid of O-linked saccharides. Analysis by lectin-affinity staining revealed the presence of complex-type oligosaccharides containing non-reducing terminal alpha-galactosyl residues and fucose residues linked to the proximal N-acetylglucosamine. Sialic acid residues could not be detected. For their structural analysis, the oligosaccharides were released by hydrazinolysis and fractionated on Bio-Gel P-4. Approximately 80% of the eluted oligosaccharides have a size equivalent of 17 +/- 2 glucose units. The major oligosaccharide representing about 45% of the total carbohydrate present in CVF was purified to homogeneity by MicroPak AX-5 HPLC and its structure was analyzed by sequential exoglycosidase digestion. The positions of the glycosidic linkages of the sugar residues were established by methylation analysis of CVF-derived glycopeptides. The data of these analyses indicated that the major oligosaccharide has a symmetrical fucosylated biantennary complex-type structure terminating with unusual alpha-galactosyl residues.
Gowda
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DC
Department of Biochemistry and Molecular Biology, Georgetown University, Washington, DC 20007.
Schultz
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Bredehorst
R
R
Vogel
C W
CW
D000818:Animals; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D004546:Elapid Venoms / Q000737:chemistry* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D008401:Gas Chromatography-Mass Spectrometry; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid; D009844:Oligosaccharides / Q000737:chemistry*; D012794:Sialic Acids / Q000032:analysis; D012911:Snakes
D004546:Elapid Venoms; D009844:Oligosaccharides; D012794:Sialic Acids; C016310:cobra venom factor; D019158:N-Acetylneuraminic Acid