title: Structures of the N-linked oligosaccharides of the membrane glycoproteins from three lepidopteran cell lines (Sf-21, IZD-Mb-0503, Bm-N).
abstract: The primary structures of the Asn-linked carbohydrate chains isolated from membrane glycoproteins of the three insect cell lines Mamestra brassicae (Mb-0503), Bombyx mori (Bm-N), and Spodoptera frugiperda (Sf-21) have been determined. Tryptic glycopeptides derived from the membrane fraction were digested with peptide-N-glycanase A. The resulting oligosaccharides were reductively aminated with 2-aminopyridine and identified by two-dimensional HPLC mapping in combination with exoglycosidase digestions. Oligomannose-type structures ranging from Man2GlcNAc2 to Man9GlcNAc2 occurred in all three cell lines. The pattern of Man5- to Man9GlcNAc2-isomers suggests an alpha-mannosidase trimming pathway very similar to that in mammalian cells. In each cell line, the small (Man2, Man3) oligosaccharides were partly fucosylated at the asparagine-linked GlcNAc residue, but distinct fucosylation patterns were observed: while only a low degree of alpha 1,3-fucosylation was detected in Sf-21 and Bm-N cells, the glycoproteins isolated from Mb-0503 cells contained 30% of alpha 1,3-fucosylated glycans, predominantly in the difucosylated form, i.e., with two fucoses linked to the same N-acetylglucosamine residue. Additionally, the following alpha 1,6-fucosylated (Bm-N cells) or difucosylated (Sf-21, Mb-0503 cells) GlcNAc-terminated structures were found: [formula: see text]
authors.affiliation: Institut für Chemie, Universität für Bodenkultur, Vienna, Austria.
authors.forename: V
authors.initials: V
authors.lastname: Kubelka
authors.forename: F
authors.initials: F
authors.lastname: Altmann
authors.forename: G
authors.initials: G
authors.lastname: Kornfeld
authors.forename: L
authors.initials: L
authors.lastname: März
mesh_terms: D000818:Animals; D012831:Bombyx; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D005643:Fucose / Q000032:analysis; D006026:Glycoside Hydrolases; D007915:Lepidoptera / Q000378:metabolism*; D008361:Mannosidases / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009036:Moths; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D043323:alpha-Mannosidase
chemical_list: D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D005643:Fucose; D006026:Glycoside Hydrolases; D008361:Mannosidases; D043323:alpha-Mannosidase