RNA encapsidation by SV40-derived nanoparticles follows a rapid two-state mechanism

Stanislav Kler, Roi Asor, Chenglei Li, Avi Ginsburg, Daniel Harries, Ariella Oppenheim*, Adam Zlotnick, Uri Raviv

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

87 Scopus citations


Remarkably, uniform virus-like particles self-assemble in a process that appears to follow a rapid kinetic mechanism. The mechanisms by which spherical viruses assemble from hundreds of capsid proteins around nucleic acid, however, are yet unresolved. Using time-resolved small-angle X-ray scattering (TR-SAXS), we have been able to directly visualize SV40 VP1 pentamers encapsidating short RNA molecules (500mers). This assembly process yields T = 1 icosahedral particles comprised of 12 pentamers and one RNA molecule. The reaction is nearly one-third complete within 35 ms, following a two-state kinetic process with no detectable intermediates. Theoretical analysis of kinetics, using a master equation, shows that the assembly process nucleates at the RNA and continues by a cascade of elongation reactions in which one VP1 pentamer is added at a time, with a rate of approximately 10 9 M -1 s -1. The reaction is highly robust and faster than the predicted diffusion limit. The emerging molecular mechanism, which appears to be general to viruses that assemble around nucleic acids, implicates long-ranged electrostatic interactions. The model proposes that the growing nucleo-protein complex acts as an electrostatic antenna that attracts other capsid subunits for the encapsidation process.

Original languageAmerican English
Pages (from-to)8823-8830
Number of pages8
JournalJournal of the American Chemical Society
Issue number21
StatePublished - 30 May 2012


Dive into the research topics of 'RNA encapsidation by SV40-derived nanoparticles follows a rapid two-state mechanism'. Together they form a unique fingerprint.

Cite this