Heterogeneity of bovine lactotransferrin glycans. Characterization of alpha-D-Galp-(1-->3)-beta-D-Gal- and alpha-NeuAc-(2-->6)-beta-D-GalpNAc-(1-->4)- beta-D-GlcNAc-substituted N-linked glycans.
Lactotransferrin isolated from a pool of mature bovine milk has been shown to contain N-glycosidically-linked glycans possessing N-acetylneuraminic acid, galactose, mannose, fucose, N-acetylglucosamine, and N-acetylgalactosamine. The glycopeptides obtained by Pronase digestion were fractionated by concanavalin A-Sepharose affinity chromatography into three fractions: slightly retained (A), retained (B), and strongly retained (C). The structure of the glycans of the three fractions has been determined by application of methanolysis, methylation analysis, fast atom bombardment-mass spectrometry, and 1H NMR spectroscopy. Diantennary structures without GalNAc were present as partially sialylated and partially (1-->6)-alpha-L-fucosylated structures in Fractions A and B. Sequences containing alpha-D-Galp-(1-->3)-beta-D-Gal on the alpha-D-Man-(1-->6) antenna, and beta-D-GalpNAc-(1-->4)-beta-D-GlcNAc and alpha-NeuAc-(2-->6)-beta-D-GalpNAc-(1-->4)-beta-D-GlcNAc on the alpha-D-Man-(1-->3) antenna were characterized in the oligosaccharide-alditols obtained by reductive cleavage of Fraction B. A series of Man4-9-GlcNAc structures were identified in Fraction C after endo-N-acetyl-beta-D-glucosaminidase digestion. These results show that the structures of bovine lactotransferrin glycans are more heterogeneous than those of previously characterized transferrin glycans.
Coddeville
B
B
Laboratoire de Chimie Biologique, Unité Mixte de Recherche du Centre National de la Recherche Scientifique No. 111, Université des Sciences et Techniques de Lille Flandres-Artois, Villenueve d'Ascq, France.
Strecker
G
G
Wieruszeski
J M
JM
Vliegenthart
J F
JF
van Halbeek
H
H
Peter-Katalinić
J
J
Egge
H
H
Spik
G
G
D000818:Animals; D001894:Borohydrides; D002417:Cattle; D005591:Chemical Fractionation; D003208:Concanavalin A / Q000737:chemistry; D006020:Glycopeptides / Q000302:isolation & purification; D007781:Lactoferrin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008697:Methane / Q000378:metabolism; D008745:Methylation; D009844:Oligosaccharides / Q000737:chemistry; D011134:Polysaccharides / Q000032:analysis*; D011522:Protons; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013402:Sugar Alcohols / Q000737:chemistry
D001894:Borohydrides; D006020:Glycopeptides; D009844:Oligosaccharides; D011134:Polysaccharides; D011522:Protons; D013402:Sugar Alcohols; D003208:Concanavalin A; C025364:sodium borohydride; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D007781:Lactoferrin; D008697:Methane