Evidence for a site-specific fucosylation of N-linked oligosaccharide of immunoglobulin A1 from normal human serum.
Glycopeptides containing the N-linked oligosaccharide from human serum IgA1 were analyzed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS). Two glycopeptides, GP1 and GP2, prepared from the endoproteinase Asp-N digest of the IgA1 heavy chain, were derived from the CH2 domain (N-glycan site at Asn263) and the tailpiece portion (N-glycan site at Asn459), respectively. The structure of the attached sugar chain was deduced from the mass number of the glycopeptide and confirmed by a two-dimensional mapping technique for a pyridylaminated oligosaccharide. GP1 was composed of two major components having a fully galactosylated bianntena sugar chain with or without a bisecting N-acetylglucosamine (GlcNAc) residue. On the other hand, the GP2 fraction corresponded to the glycopeptides having a fully galactosylated and fucosylated bianntena sugar chain partly bearing a bisecting GlcNAc residue. Thus, the site-specific fucosylation of the N-linked oligosaccharide on the tailpiece of the alpha1 chain became evident for normal human serum IgA1.
Tanaka
A
A
Analytical Research Laboratory, Asahi Chemical Industry Co., Ltd., Fuji, Shizuoka, Japan.
Iwase
H
H
Hiki
Y
Y
Kokubo
T
T
Ishii-Karakasa
I
I
Toma
K
K
Kobayashi
Y
Y
Hotta
K
K
D000595:Amino Acid Sequence; D002240:Carbohydrate Sequence; D005643:Fucose / Q000378:metabolism*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood* / Q000737:chemistry; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D007070:Immunoglobulin A; D009844:Oligosaccharides; D005643:Fucose