title: N-linked oligosaccharides of cobra venom factor contain novel alpha(1-3)galactosylated Le(x) structures.
abstract: Cobra venom factor (CVF), a nontoxic, complement-activating glycoprotein in cobra venom, is a functional analog of mammalian complement component C3b. The carbohydrate moiety of CVF consists exclusively of N-linked oligosaccharides with terminal alpha1-3-linked galactosyl residues, which are antigenic in human. CVF has potential for several medical applications, including targeted cell killing and complement depletion. Here, we report a detailed structural analysis of the oligosaccharides of CVF. The structures of the oligosaccharides were determined by lectin affinity chromatography, antibody affinity blotting, compositional and methylation analyses, and high-resolution (1)H-NMR spectroscopy. Approximately 80% of the oligosaccharides are diantennary complex-type, approximately 12% are tri- and tetra-antennary complex-type, and approximately 8% are oligomannose type structures. The majority of the complex-type oligosaccharides terminate in Galalpha1-3Galbeta1-4(Fucalpha1-3)GlcNAcbeta1, a unique carbohydrate structural feature abundantly present in the glycoproteins of cobra venom.
authors.affiliation: Department of Biochemistry and Molecular Biology, and Vincent T. Lombardi Cancer Center, Georgetown University Medical Center, 3900 Reservoir Road, NW, Washington, DC 20007, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Gowda
authors.forename: J
authors.initials: J
authors.lastname: Glushka
authors.lastname: Halbeek Hv
authors.forename: R N
authors.initials: RN
authors.lastname: Thotakura
authors.forename: R
authors.initials: R
authors.lastname: Bredehorst
authors.forename: C W
authors.initials: CW
authors.lastname: Vogel
mesh_terms: D002240:Carbohydrate Sequence; D002846:Chromatography, Affinity; D004546:Elapid Venoms / Q000737:chemistry*; D005690:Galactose / Q000737:chemistry; D006020:Glycopeptides / Q000737:chemistry; D016256:Lewis X Antigen / Q000737:chemistry*; D013058:Mass Spectrometry; D008745:Methylation; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry*
chemical_list: D004546:Elapid Venoms; D006020:Glycopeptides; D016256:Lewis X Antigen; D009844:Oligosaccharides; C016310:cobra venom factor; D005690:Galactose