The glycoprotein of measles virus. External radioactive labelling of its carbohydrate and partial characterization of the glycopeptide

Abstract

Measles virus was propagated in VERO cells and purified from the culture supernatants by two successive tartrate-density-gradient centrifugations. Surface carbohydrates were labelled both in vitro and in vivo with 3H after treatment with galactose oxidase/NaB3H4 or with [3H]glucosamine. The major labelled glycoprotein in measles virions had a mol.wt. of 79 000. After labelling with periodate/NaB3H4, which would result in specific labelling of sialic acid residues, the 79 000-mol.wt. glycoprotein was very weakly labelled. This suggests that there is no or a very low amount of sialic acid in the virions. Further analysis of the glycoprotein showed that galactose is the terminal carbohydrate unit in the oligosaccharide, and the molecular weight of the glycopeptide obtained after Pronase digestion is about 3000. The oligosaccharide is attached to the polypeptide through an alkali-stable bond, indicating a N-glycosidic asparagine linkage.