The polypeptides of human parainfluenza type 2 virus and their synthesis in infected cells

We have studied the structural components of three strains of human parainfluenza virus type 2 (HPI-2) and identified the virus-specific polypeptides. Molecular weight of P and F1 polypeptides determined by us, when compared with that reported previously, was in reversed order. HN polypeptide existed chiefly as disulfide-linked dimers in cells infected with Toshiba strain, while as monomers and dimers in nearly equal proportion in cells infected with two other strains. Similar disulfide-linked NP oligomers were found in cells infected with all three strains. F1 and F2, cleaved forms of F protein, could be detected in cells infected with all three strains, but the ratio of cleaved (F1 and F2) to uncleaved (F0) forms was markedly lower in 62-M 786- and 63-M 1-infected than in Toshiba strain-infected cells. However, there was no difference of oligopeptide mapping patterns and isoelectric point of F polypeptide between Toshiba and 62-M 786 strains. By contrast, oligopeptide mapping patterns of HN protein of Toshiba strain differed from those of the two other strains. Furthermore, the HN polypeptide of Toshiba strain was phosphorylated in the infected Vero cells, but that of the other two strains was not.