Characterization of the structural proteins of different strains of Newcastle disease virus.

Abstract

SUMMARY The structural proteins of 14 strains of Newcastle disease virus (NDV) were examined on reduced polyacrylamide gels. Three major and seven minor virus proteins (VP) were found reproducibly, one of the major and one of the minor poly-peptides being glycoproteins (VGP). The three major polypeptides had mol. wt. of 75000 (VGP75), 55000 (VP55) and 42000 (VP42) and the minor polypeptides 180000 (VP180), 110000 (VP110), 55000 (VGP55), 53000 (VP53), 52000 (VP52), 51000 (VP51) and 49000 (VP49). On polyacrylamide gel electrophoresis in a non-reduced system one of the minor components, VGP55, migrated to an apparently higher mol. wt. position (between VGP75 and VP55) with all strains of virus examined. Under the same conditions, it was found that VGP75 from some strains was either absent or present in greatly diminished amounts, and a new high mol. wt. glycoprotein appeared. By extraction of this high mol. wt. protein from non-reduced polyacrylamide gels, and electrophoresis of the reduced protein under reduced conditions the major component was found to be VGP75, but VP55 was also present. Amino acid analysis of the three major proteins from three strains of virus showed clear differences between the proteins of the different strains.