Virus-like particles of Maize rayado fino virus, Cucumber mosaic virus, and Lolium latent virus as chemical bio-conjugate substrates

Plant viruses and virus-like particles (VLPs) are highly organized structures with unique chemical and physical properties. These properties can be exploited to generate nano-materials which have multiple uses. Novel VLPs can be produced by either genetically modifying the viral genome or by chemically attaching in vitro a variety of ligands, including fluorescent dyes, polymers, peptides and carbohydrates, to reactive groups on the viral capsids. Each of the subunits forming the VLPs potentially represents a platform to display functional groups, with control over spacing and orientation. Combining molecular biology, chemistry, and nanotechnology techniques, we explored the possibility to perform chemical modifications on the isometric VLPs of Maize rayado fino virus and Cucumber mosaic virus and the flexuous Lolium latent virus. The orthogonal reactivity and the suitability to serve as chemical bio-conjugate substrates was tested using cysteine side chain thiol-reactive probes including fluorescein-5-maleimide and lysine side chain amine-labeling reagents, including NHS-Fluorescein. Fluorescently labelled particles were analyzed by SDS-PAGE and by biotinylation assays demonstrating the feasibility of these reactive amino acids to be used in more advanced conjugation chemistries.