Characterization of N- and O-linked oligosaccharides of glycoprotein 350 from Epstein-Barr virus.
Glycoprotein 350 (gp350), the major Epstein-Barr Virus (EBV) envelope glycoprotein, has extensive N- and O-linked oligosaccharide chains. To characterize these oligosaccharide chains, [3H]glucosamine-labeled gp350 was isolated from an EBV transformed marmoset lymphoblastoid cell line (B95-8) induced to replicate EBV. Radiolabeled pronase-glycopeptides were fractionated by serial affinity chromatography and O-linked oligosaccharides released by mild alkaline borohydride treatment. Virtually all (99%) N-linked oligosaccharides were of complex type, with a predominance of tri-tetraantennary versus diantennary chains. A significant portion (28%, in term of radioactivity) of the tri-tetraantennary chains bound to leucoagglutinin-agarose, indicating an additional branch in beta(1-6)-linkage to the trimannosyl core. N-linked oligosaccharides with such a branching pattern have not been previously described in any herpesvirus glycoprotein, but have been associated with neoplastic transformation. Half of [3H]glucosamine incorporated into gp350 was recovered in O-linked oligosaccharides. The smallest chains have a core beta Gal-GalNAc disaccharide structure. Most O-linked chains have two to three N-acetylglucosamine and one N-acetylgalactosamine residues, besides the N-acetylgalactosamine residue located at the terminal reducing end, suggesting a di- or tri- N-acetyllactosamine structure. Consistent with such a structure, the size of these chains, after sialic acid removal, was that of an heptasaccharide or larger.
Serafini-Cessi
F
F
Dipartimento di Patologia Sperimentale, Università degli Studi di Bologna, Italy.
Malagolini
N
N
Nanni
M
M
Dall'Olio
F
F
Campadelli-Fiume
G
G
Tanner
J
J
Kieff
E
E
D002846:Chromatography, Affinity; D003208:Concanavalin A; D006031:Glycosylation; D004854:Herpesvirus 4, Human / Q000032:analysis*; D008562:Membrane Glycoproteins / Q000032:analysis*; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis; D011499:Protein Processing, Post-Translational; D014759:Viral Envelope Proteins / Q000032:analysis*
D008562:Membrane Glycoproteins; D009844:Oligosaccharides; D014759:Viral Envelope Proteins; D003208:Concanavalin A