Analysis of viral glycoproteins by glycosidic digestion inside a polyacrylamide gel

We adapted the method described by Cleveland et al. (1977); (Peptide mapping by limited proteolysis in sodium dodecyl sulphate and analysis by gel electrophoresis. J. Biol. Chem. 252, 1102-1106) to study the glycosidic residues linked to the viral glycoproteins of two enveloped viruses: Junin virus (JV) and rubella virus (RV). Radioiodinated glycoproteins were obtained from purified virions, isolated from SDS-polyacrylamide gels and then hydrolysed by specific glycosidases inside a second gel. N-linked oligosaccharides, mannose and galactose were found as terminal residues in the JV-G1 glycoprotein. Mannose and N-glycans of complex hybrid type were present on RV glycoproteins.