Monday, June 3, 2013
The Origin of Negative Overcharge in RNA Viruses
Zhen-gang Wang, Professor of Chemical Engineering, Division of Chemical Engineering, California Institute of Technology
Most naturally occurring RNA-based viruses are negatively overcharged, that is, the total negative charge on the RNA exceeds the positive charge carried by the capsid proteins. In this talk, I offer an explanation of this phenomenon based on consideration of the salt condition inside the cell where viral assembly takes place. The presence of mostly negatively charged macromolecules in the cellular milieu generates a substantial negative potential (the Donnan potential) relative to a monovalent salt solution. This Donnan potential provides a major driving force for the viral assembly and is responsible for the prevalence of negatively overcharged RNA viruses in Nature.