Scaffolding protein regulates the polymerization of P22 coat subunits into icosahedral shells in vitro

摘要: Coat and scaffolding subunits derived from P22 procapsids have been purified in forms that co-assemble rapidly efficiently into icosahedral shells vitro under native conditions. The half-time for this reaction is approximately five minutes at 21 degrees C. exhibits the regulated features observed vivo. Neither coat nor alone self-assemble large structures. Upon mixing together they polymerize procapsid-like with vivo protein composition. preparations are monomeric. appear to be monomeric or dimeric. These results confirm procapsid formation does not proceed through assembly of a core scaffolding, which then organizes coat, but requires copolymerization scaffolding. To explore mechanisms control polymerization, shell was examined as function input ratio subunits. indicated required both initiation continued polymerization. Though produced contain about 300 molecules fewer could assembled down lower limit 140 per shell. overall these experiments indicate must interact growth phases assembly. However, it remains unclear whether during form mixed oligomer prior adding occurs growing edge.