title: The carbohydrates of mouse hepatitis virus (MHV) A59: structures of the O-glycosidically linked oligosaccharides of glycoprotein E1.
abstract: Two size classes of O-glycosidically linked oligosaccharides were liberated from glycoprotein E1 of mouse hepatitis virus (MHV) A59 by reductive beta-elimination and separated by h.p.l.c. The structures of the reduced oligosaccharides were determined by successive exoglycosidase digestions and by methylation analyses involving combined capillary gas chromatography-mass spectrometry and mass fragmentography after chemical ionization with ammonia. Oligosaccharide A (Neu5Ac alpha 2----3 Gal beta 1----3 GalNAc) comprised 35% of the total carbohydrate side chains, while the remaining 65% of the oligosaccharides of E1 had the branched structure B: Neu5Ac alpha 2----3 Gal beta 1----3 (Neu5Ac alpha 2----6) GalNAc. Both oligosaccharides were linked to the E1 polypeptide via N-acetylgalactosamine, and 20% of the sialic acids present in E1 glycopeptides were found to consist of N-acetyl-9-mono-O-acetylneuraminic acid. The reported structures of the O-linked glycans are discussed in the context of the amino acid sequence of E1, which exhibits a cluster of four hydroxyamino acids (Ser-Ser-Thr-Thr) as potential O-glycosylation sites at the amino terminus. Oligosaccharides with identical structures and an identical O-glycosylated tetrapeptide sequence are present in the blood group M-active glycophorin A of the human erythrocyte membrane.
mesh_terms: D002240:Carbohydrate Sequence; D006023:Glycoproteins / Q000032:analysis*; D008745:Methylation; D006517:Murine hepatitis virus / Q000032:analysis*; D009844:Oligosaccharides / Q000032:analysis; D010084:Oxidation-Reduction; D012794:Sialic Acids / Q000032:analysis; D013329:Structure-Activity Relationship; D014764:Viral Proteins / Q000032:analysis*
chemical_list: D006023:Glycoproteins; D009844:Oligosaccharides; D012794:Sialic Acids; D014764:Viral Proteins