title: Characterization and role in morphogenesis of a new subviral particle (55S) isolated from poliovirus-infected cells.
abstract: A previously undetected subviral particle, designated the 55S particle because of its position in sucrose density gradients, has been found in cytoplasmic extracts of poliovirus-infected cells. It contains no RNA, is composed of equimolar amounts of the structural polypeptides P1AB, P1C, and P1D, and is stable in vitro under a variety of conditions: presence or absence of EDTA, dilution in low- or high-ionic-strength buffers, suspension in buffers up to pH 10, incubation at 37 degrees C, and centrifugation to equilibrium in CsCl gradients (where it bands at a density of 1.285 g/cm3). Conventional pulse-chase experiments show that 55S particles are the products of the assembly of 14S subunits and the precursors of virions. These data led to the formulation of a model of poliovirus morphogenesis in which the conversion of capsomers into 73S empty capsids does not occur directly, but through the formation of an intermediate structure, the 55S particle.
mesh_terms: D002460:Cell Line; D006367:HeLa Cells / Q000166:cytology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D009024:Morphogenesis; D009994:Osmolar Concentration; D010455:Peptides / Q000032:analysis; D017955:Poliovirus / Q000302:isolation & purification* / Q000648:ultrastructure; D014764:Viral Proteins / Q000032:analysis
chemical_list: D010455:Peptides; D014764:Viral Proteins