Polypeptides of pneumonia virus of mice. II. Characterization of the glycoproteins.
The kinetics of synthesis and the nature of the oligosaccharides of the glycoproteins of pneumonia virus of mice (PVM) were studied. Tryptic peptide mapping showed that the two major glycosylated polypeptides G1 and G2 were different forms of the same protein. G2 was derived from G1 which in turn appeared to be derived from an unidentified precursor. The G1/G2 protein of PVM is probably a haemagglutinin since a monoclonal antibody directed against it has a high haemagglutination inhibition titre. On the basis of experiments with inhibitors and glycosidases it was deduced that G1 and G2 have both N-linked and O-linked oligosaccharides. The putative fusion protein-equivalent of PVM was shown to possess N-linked oligosaccharides. In the presence of tunicamycin a high mobility form (F1t) appeared to be derived from a precursor (F0t) with the same mobility as the fully glycosylated protein. If by analogy with other paramyxoviruses this represents a cleavage event, the difference in mobility of the precursor and product suggests that the putative F2 product is smaller than the corresponding F2 protein of other paramyxoviruses. However, no F2 candidate protein was detected and evidence for an F1,2 dimer was inconclusive. The glycoproteins of PVM resemble those of respiratory syncytial virus in terms of their pattern of glycosylation, but differ in their processing.
Ling
R
R
Department of Biological Sciences, University of Warwick, Coventry, U.K.
Pringle
C R
CR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D002478:Cells, Cultured; D006023:Glycoproteins / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology; D006031:Glycosylation; D006385:Hemagglutination Inhibition Tests; D051379:Mice; D009844:Oligosaccharides / Q000032:analysis / Q000096:biosynthesis / Q000276:immunology; D010252:Paramyxoviridae / Q000032:analysis* / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D010452:Peptide Biosynthesis; D010449:Peptide Mapping; D010455:Peptides / Q000032:analysis* / Q000276:immunology; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D014415:Tunicamycin / Q000494:pharmacology; D014764:Viral Proteins / Q000032:analysis* / Q000096:biosynthesis / Q000276:immunology
D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D009844:Oligosaccharides; D010455:Peptides; D014764:Viral Proteins; D014415:Tunicamycin