SUPRAMOLECULAR ASSEMBLIES |
Packaging of a Polymer by a Viral Capsid: The Interplay Between Polymer Length and Capsid Size
Yufang Hu 1, Roya Zandi 2, Adriana Anavitarte 1, Charles M. Knobler 3* and William M. Gelbart 1
1 UCLA
2 University of California, Riverside
3 University of California - LA
* To whom correspondence should be addressed. E-mail: knobler{at}chem.ucla.edu.
Submitted on August 9, 2007
Revised on September 16, 2007
Accepted on 10 October 2007
 |
Abstract |
|---|
We report a study of the in vitro self-assembly of virus-like-particles formed by the capsid protein of Cowpea Chlorotic Mottle Virus and the anionic polymer poly(styrene sulfonate) (PSS) for five molecular weights ranging from 400 kDa to 3.4 MDa. The goal is to explore the effect on capsid size of the competition between the preferred curvature of the protein and the molecular weight of the packaged cargo. The capsid size distribution for each polymer was unimodal, but two distinct sizes were observed – 22 nm for the lower molecular weights, and jumping to 27 nm at a molecular weight of 2 MDa. A model is provided for the formation of the virus-like-particles that accounts for both the PSS and capsid protein self-interactions and the interactions between the protein and PSS. Our study suggests that the size of the encapsidated polymer cargo is the deciding factor for the selection of one distinct capsid size from several possible sizes bearing the same inherent symmetry.
Key Words:
Self-assembly, discretized capsid sizes, packaging efficiency, polyelectrolyte confinement, preferred curvature, virus-like particle
