title: Identification of high-mannose and multiantennary complex-type N-linked glycans containing alpha-galactose epitopes from Nurse shark IgM heavy chain.
abstract: MALDI-TOF mass spectrometry, negative ion nano-electrospray MS/MS and exoglycosidase digestion were used to identify 36 N-linked glycans from 19S IgM heavy chain derived from the nurse shark (Ginglymostoma cirratum). The major glycan was the high-mannose compound, Man(6)GlcNAc(2) accompanied by small amounts of Man(5)GlcNAc(2), Man(7)GlcNAc(2) and Man(8)GlcNAc(2). Bi- and tri-antennary (isomer with a branched 3-antenna) complex-type glycans were also abundant, most contained a bisecting GlcNAc residue (beta1-->4-linked to the central mannose) and with varying numbers of alpha-galactose residues capping the antennae. Small amounts of monosialylated glycans were also found. This appears to be the first comprehensive study of glycosylation in this species of animal. The glycosylation pattern has implications for the mechanism of activation of the complement system by nurse shark IgM.
authors.affiliation: Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. david.harvey@bioch.ox.ac.uk
authors.forename: David J
authors.initials: DJ
authors.lastname: Harvey
authors.forename: Max
authors.initials: M
authors.lastname: Crispin
authors.forename: Beryl E
authors.initials: BE
authors.lastname: Moffatt
authors.forename: Sylvia L
authors.initials: SL
authors.lastname: Smith
authors.forename: Robert B
authors.initials: RB
authors.lastname: Sim
authors.forename: Pauline M
authors.initials: PM
authors.lastname: Rudd
authors.forename: Raymond A
authors.initials: RA
authors.lastname: Dwek
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis* / Q000737:chemistry; D005690:Galactose / Q000032:analysis*; D007143:Immunoglobulin Heavy Chains / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D008358:Mannose / Q000032:analysis*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry; D012754:Sharks / Q000276:immunology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000939:Epitopes; D007143:Immunoglobulin Heavy Chains; D007075:Immunoglobulin M; D011134:Polysaccharides; D008358:Mannose; D005690:Galactose