RESUMO
The structural proteins of three mutants of simian virus 40 (SV40) which differ in plaque size, temperature sensitivity, oncogenicity, host cell restriction, and immunological properties were studied. The polypeptide components of these SV40 strains could not be distinguished by their polyacrylamide gel electrophoretic patterns. When the dissociated virions of two of the mutants were analyzed by the isoelectric focusing technique in a urea gradient, the capsid protein peaks were found to differ significantly in their isoelectric points. The capsid protein of the small-plaque mutant had an isoelectric point of pH 6.51 as compared with pH 6.28 for the large-plaque strain. Isoelectric focusing of the isolated capsid protein revealed three components, a single major subunit and two minor forms. The coat proteins of two of the mutants, small-plaque and minute-plaque strains, were indistinguishable by this technique. The capsid protein peaks obtained by isoelectric focusing were further analyzed by polyacryalmide gel electrophoresis.
Assuntos
Mutação , Vírus 40 dos Símios/crescimento & desenvolvimento , Proteínas Virais , Animais , Isótopos de Carbono , Linhagem Celular , Técnicas de Cultura , Eletroforese em Gel de Poliacrilamida , Haplorrinos , Focalização Isoelétrica , Rim , Peso Molecular , Peptídeos/análise , Vírus 40 dos Símios/análise , Vírus 40 dos Símios/imunologia , Vírus 40 dos Símios/patogenicidade , Temperatura , Trítio , Proteínas Virais/análiseRESUMO
Sodium dodecyl sulfate acrylamide gel electrophoresis of the solubilized proteins from purified simian virus 40 (SV40) virions revealed two major and two minor structural polypeptide components. The major components which comprise over 75% of the total virion were shown to be the capsid proteins by immunological and isoelectric focusing fractionation analysis. These two polypeptides have estimated molecular weights of 45,000 daltons as determined by gel electrophoresis. One of the two minor components was identified as the nucleocapsid protein and has an approximate molecular weight of 16,000. The other unidentified minor component has an average molecular weight of 29,000.
Assuntos
Vírus 40 dos Símios/análise , Proteínas Virais/análise , Aminoácidos , Animais , Antígenos/análise , Isótopos de Carbono , Linhagem Celular , Centrifugação com Gradiente de Concentração , Césio , Cloretos , Eletroforese Descontínua , Haplorrinos , Soros Imunes , Imunodifusão , Focalização Isoelétrica , Rim , Peso Molecular , Peptídeos/análise , Peptídeos/isolamento & purificação , Coelhos , Vírus 40 dos Símios/crescimento & desenvolvimento , Vírus 40 dos Símios/imunologia , Vírus 40 dos Símios/isolamento & purificação , Sódio , Sacarose , Sulfatos , Timidina , Trítio , Proteínas Virais/isolamento & purificação , Cultura de VírusRESUMO
Intact wild-type simian virus 40 particles can be separated and resolved from a temperature-sensitive mutant and from a number of other viruses by agarose gel electrophoresis. The relative mobilities of the viruses appear to be a function of both virion size and surface composition. The virions of a temperature-sensitive strain of simian virus 40, tsB204, have significantly greater mobility than those of wild-type simian virus 40, when electrophoresis was conducted toward the cathode at pH 5.0. When electrophoresis was performed toward the anode at pH 7.0, TSB204 viruses have a slightly slower mobility as compared with that of the wild type. The data indicated that the virions of tsB204 have a greater positive charge at their surface than those of wild-type particles. No differences were detected in the finger print patterns of the tryptic peptides of VP1 and VP3 of these two virus strains. Although it was not possible to identify the structural polypeptide directly affected by the tsB204 mutation, we have shown that this mutation affects charge distribution on the surface of the virion.