title: Structure and assembly of turnip crinkle virus. II. Mechanism of reassembly in vitro.
abstract: Dissociation of turnip crinkle virus (TCV) at elevated pH and ionic strength produces free dimers of the coat protein and a ribonucleoprotein complex that contains the viral RNA, six coat-protein subunits, and the minor protein species, p80 (a covalently linked coat-protein dimer). This "rp-complex" is stable for several days in high salt at pH 8.5. Reassembly of TCV can be accomplished under physiological conditions, using isolated coat protein and either rp-complex or protein-free RNA. If rp-complex is used in reassembly, the same subunits remain bound to RNA on subsequent dissociation; if free RNA is used, rp-complex is regenerated. In both cases, the assembly is selective for viral RNA in competition experiments with heterologous RNA. Electron microscopy shows that assembly proceeds by continuous growth of a shell from an initiating structure, rather than by formation of distinct intermediates. We suggest that rp-complex is the initiating structure, suggest a model based on the organization of the TCV particle, and propose a mechanism for TCV assembly.
mesh_terms: D002213:Capsid; D002499:Centrifugation, Density Gradient; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D008954:Models, Biological; D010942:Plant Viruses / Q000254:growth & development* / Q000648:ultrastructure; D012328:RNA Viruses / Q000254:growth & development* / Q000648:ultrastructure; D012367:RNA, Viral / Q000378:metabolism
chemical_list: D012367:RNA, Viral