title: In vitro assembly of the outer shell of bacteriophage phi 6 nucleocapsid.
abstract: Following dissociation of bacteriophage phi 6 nucleocapsid (NC) by EDTA, a particle composed of protein P8 and corresponding to the outer shell of the NC was assembled in vitro in the presence of Ca2+ and Mg2+. Assembly was obtained from soluble protein constituents above 100 micrograms/ml and was optimal within a temperature range of 22-30 degrees. Assembly did not require the presence of genomic RNA. Crosslinking results of intact NCs and in vitro-assembled outer shells suggested that protein P8 dimers are the structural subunits of the shell. Analysis of the assembly kinetics by electron microscopy suggested that ring-like particles of uniform size, packed in flat hexagonal arrays, are intermediates in outer shell assembly.
mesh_terms: D001435:Bacteriophages / Q000648:ultrastructure*; D002213:Capsid; D002413:Cations, Divalent; D002474:Cell-Free System; D007163:Immunosorbent Techniques; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008970:Molecular Weight; D009024:Morphogenesis; D012367:RNA, Viral / Q000378:metabolism; D012995:Solubility; D013696:Temperature; D013997:Time Factors; D014758:Viral Core Proteins; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D046911:Macromolecular Substances; D012367:RNA, Viral; D014758:Viral Core Proteins; D014764:Viral Proteins