Controlled Encapsidation of Gold Nanoparticles by a Viral Protein Shell

摘要

Plant virion capsids have desirable packaging and self-assembly properties that make them ideal structures for nanotechnology.For example,both host-guest chemistry and supramolecular assembly have been demonstrated using the self-assembly of icosahedral virus capsids as a scaffold.Herein we demonstrate the templated self-assembly of the Red Clover necrotic mosaic virus (RCNMV) coat protein (CP) around gold nanoparticles.RCNMV is an icosahedral virus composed of 180 CP subunits and a triangulation number of 3 (T = 3).The RCNMV genome is bipartite and comprised of a 3.9 kB polycistronic RNA-1 and a 1.4 kB monocistronic RNA-2.Although the X-ray crystal structure of RCNMV has not been determined,an 8.0 A resolution cryoelectron microscopic reconstruction of a virion and a homology model of the CP have been generated.Assembly of RCNMV and many other T = 3 viruses is stabilized by an internal protein/RNA cage.Assembly of RCNMV begins with a specific recognition of a virion RNA sequence,the origin of assembly (OAS),by the CP.The binding of the CP to the OAS initiates the assembly process that results in the encapsidation of the viral genome.The RCNMV OAS consists of a complex of RNA-1 with an RNA-2 stem loop previously termed the trans-activator.Insertion or attachment of the RCNMV RNA-2 stem loop to a foreign viral RNA results in packaging of the foreign RNA into virions possessing a wild-type morphology.