Structure of the major oligosaccharides in the fusion glycoprotein of Newcastle disease virus

The fusion glycoprotein (F0) was isolated from Newcastle disease virus (NDV) particles metabolically labelled with [2‐3H]mannose; it was successively digested with protease and with endo‐β‐N‐acetylglucosaminidase from Streptomyces griseus. In this manner, the majority of the oligosaccharides in NDV F0 could be liberated. After reduction with NaBH4, they were separated by high‐performance liquid chromatography, and were subjected to structural analysis. Using micromethylation/capillary gas chromatography/mass fragmentography, α‐mannosidase digestion, and acetolysis, it was found that the enzymatically released NDV F0 oligosaccharides are common oligomannosidic glycoprotein glycans of size classes (Man)8GlcNAc, (Man)7GlcNAc, (Man)6GlcNAc, (Man)9GlcNAc, and (Man)5GlcNAc (in order of prevalence). The major structural isomers present in the NDV F0(Man)8GlcNAc to (Man)5GlcNAc fractions were shown to lack mannose residues D2, D1D2 or D2D3, D1D2D3, and CD1D2D3, respectively, of (Man)9GlcNAc: