Abstract Charles Knobler

The simplest viruses consist of a protein shell called the capsid that surrounds and protects the viral genome, which is often single-stranded RNA. It is remarkable that some of these viruses can self-assemble in vitro to form infectious particles indistinguishable from those that are formed in vivo. A notable example is cowpea chlorotic mottle virus (CCMV), for which the capsids are icosahedral nanoparticles 28 nm in diameter made up of 180 copies of a single 190-residue protein and each containing a 3000-nucleotide-long RNA. The protein is promiscuous; it can self-assemble into capsids around the RNAs of other viruses, anionic organic polymers such as poly(styrene sulfonate), and nanoemulsion droplets and quantum dots that are negatively charged. Moreover, under appropriate conditions the CCMV capsid protein can self-assemble into empty capsids, tubes and multi-shell structures. Although much of the structural repertoire of CCMV has been recognized since the late 1960’s, recent experimental and theoretical studies and simulations have made clearer the underlying physical principles involved in the assembly processes and these will be the focus of my talk.