Monosaccharide Sequence of Protein-Bound Glycans of Uukuniemi Virus

Marja Pesonen, Esa Kuismanen, Ralf F. Pettersson
1982 Journal of Virology  
Uukuniemi virus, a member of the Bunyaviridae family, was grown in BHK-21 cells in the presence of [3H]mannose. The purified virions were disrupted with sodium dodecyl sulfate and digested with pronase. The [3H]mannose-labeled glycopeptides of the mixture of the two envelope glycoproteins Gl and G2 were characterized by degrading the glycans with specific exo-and endoglycosidases, by chemical methods, and by analyzing the products with lectin affinity and gel chromatography. The glycopeptides
more » ... The glycopeptides of Uukuniemi virus fell into three categories: complex, high-mannose type, and intermediate. The complex glycopeptides probably contained mainly two NeuNAc-Gal-GlcNAc branches attached to a core (Man)3(GlcNAc)2 peptide. The high-mannose-type glycans were estimated to contain at least five mannose units attached to two N-acetylglucosamine residues. Both glycan species appeared to be similar to the asparagine-linked oligosaccharides found in many soluble and membrane glycoproteins. The results suggested that the intermediate glycopeptides contained a mannosyl core. In about half of the molecules, one branch appeared to be terminated in mannose, and one appeared to be terminated in N-acetylglucosamine. Such glycans are a novel finding in viral membrane proteins. They may represent intermediate species in the biosynthetic pathway from high-mannose-type to complex glycans. Their accumulation could be connected with the site of maturation of the members of the Bunyaviridae family. Electron microscopic data suggest that the virions bud into smooth-surfaced cistemae in the Golgi region. The relative amounts of [3H]mannose in the complex, high-mannose-type, and intermediate glycans were 25, 62, and 13%, respectively, which corresponded to the approximate relative number of oligosaccharide chains of 2:2.8:1, respectively, in the roughly equimolar mixture of GI and G2. Endoglycosidase H digestion of isolated [3 5S]methio-390 on May 7, 2020 by guest
doi:10.1128/jvi.41.2.390-400.1982 fatcat:hsm7jhogynbujdjn3kh3utsbke