title: Uncatalyzed assembly of spherical particles from SV40 VP1 pentamers and linear dsDNA incorporates both low and high cooperativity elements.
abstract: The capsid of SV40 virion is comprised of 72 pentamers of the major capsid protein, VP1. We examined the synergism between pentamer-pentamer interaction and pentamer-DNA interaction using a minimal system of purified VP1 and a linear dsDNA 600-mer, comparing electrophoresis with electron microscopy and size exclusion chromatography. At low VP1/DNA ratios, large tubes were observed that apparently did not survive native agarose gel electrophoresis. As the VP1 concentration increased, electrophoretic migration was slower and tubes were replaced by 200 A diameter particles and excess free pentamer. At high VP1/DNA ratios, a progressively larger fraction of particles was similar to 450 A diameter virions. VP1 association with DNA is very strong compared to the concentrations in these experiments yet, paradoxically, stable complexes appear only at high ratios of VP1 to DNA. These data suggest a DNA saturation-dependent nucleation event based on non-specific pentamer-DNA interaction that controls assembly and the ultimate capsid geometry.
authors: Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
authors: Santanu
authors: S
authors: Mukherjee
authors: Stanislav
authors: S
authors: Kler
authors: Ariella
authors: A
authors: Oppenheim
authors: Adam
authors: A
authors: Zlotnick
mesh_terms: D036022:Capsid Proteins / Q000378:metabolism*; D002850:Chromatography, Gel; D004279:DNA, Viral / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D046911:Macromolecular Substances / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D011485:Protein Binding; D055503:Protein Multimerization; D013539:Simian virus 40 / Q000502:physiology*; D019065:Virus Assembly
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D046911:Macromolecular Substances; C062481:VP1 protein, polyomavirus