In vitro assembly of poliovirus 14 S subunits: identification of the assembly promoting activity of infected cell extracts.
Purified poliovirus 14 S subunits are assembled into empty capsids in vitro only if their concentration exceeds a 1.6 nM threshold. This also holds true for the 14 S subunits in unpurified extracts of infected cells. Such an extract may promote the assembly of extraneous 14 S subunits, but only if it contributes enough 14 S subunits to raise their total concentration over the threshold. As a result of assembly, the concentration of 14 S subunits in an infected cell extract decreases exponentially, with a half life of 15 min at 37 degrees. When purified 14 S subunits of serotype 1 are mixed with extracts of cells infected with type 2 or 3, chimeric empty capsids are formed, thus showing the pooling of endogenous and extraneous 14 S subunits. In conclusion, the assembly promoting activity of infected cell extracts amounts to nothing more than the supply of endogenous 14 S subunits.
Rombaut
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B
Department of Microbiology and Hygiene, Vrije Universiteit Brussel, Belgium.
Foriers
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A
Boeyé
A
A
D000911:Antibodies, Monoclonal; D002213:Capsid / Q000096:biosynthesis / Q000378:metabolism*; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D046911:Macromolecular Substances; D008715:Methionine / Q000378:metabolism; D017955:Poliovirus / Q000502:physiology*; D013462:Sulfur Radioisotopes
D000911:Antibodies, Monoclonal; D046911:Macromolecular Substances; D013462:Sulfur Radioisotopes; D008715:Methionine