SV40 assembly in vivo and in vitro

摘要: The Simian virus 40 (SV40) capsid is a T = 7d icosahedral lattice ∼45 nm in diameter surrounding the ∼5 kb circular minichromosome. outer shell composed of 360 monomers major protein VP1, tightly bound 72 pentamers. VP1 jellyroll β-barrel, with extending N- and C-terminal arms. N-terminal arms bind DNA face interior capsid. flexible C-arms tie together pentamers three distinct kinds interactions, thus facilitating formation T = 7 icosahedron from identical pentameric building blocks. Assembly vivo was shown to occur by addition capsomers around DNA. We apply combination biochemical genetic approaches study SV40 assembly. Our vitro studies suggest following model: one or two at high affinity ses, viral encapsidation signal, forming nucleation centre for Next, multiple attach concomitantly, lower affinity, This increases their local concentration rapid, cooperative assembly reaction. Formation proceeds either gradual single growing concerted pentamer clusters.