Characterization of carbohydrates linked to rubella virus glycoprotein E2.

Rubella virus contains two envelope glycoproteins, E1 and E2. The amino acid sequence for both glycoproteins is known, as is the number of N-glycosylation sites. This study has demonstrated the presence of O-linked carbohydrates bound to E2 and determined structural characteristics of the N-linked oligosaccharide chains. O-linked sugars were found to be resistant to digestion with N-glycanase but sensitive to beta-elimination with alkaline borohydride. After treatment with neuraminidase, O-linked sugars bound to peanut agglutinin, suggesting the presence of the disaccharide galactose-N-acetylgalactosamine, masked by sialic acid. The N-linked oligosaccharides were large, probably four-branched, and showed a lectin binding pattern suggesting the complex type, with terminal Gal, GlcNAc and sialic acid. No Endo H-sensitive carbohydrates were detected.