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Virus-Like-Particles as chemical bioconjugation substrates

 

Biconjugation can be achieved by chemically attaching in vitro synthesized molecules to reactive groups on the virus particles' surface using an array of bioconjugation reactions. In order to design reliable platforms for chemical reactions, it is important to analyze the structure of the coat proteins, the presence of reactive amino acids capable to function as substrate in chemical conjugation, and if necessary, install through mutagenesis a range of attachment sites at different locations on the VLPs.

 

Purified VLPs can be used to covalently display different molecules that confer diverse functionality. The number of the molecules displayed on the exterior viral surface can be controlled by a combination of the number of attachment sites introduced into each subunit forming the VLPs and the number of subunits assembled into the final capsid structure. The ligands, can also be displayed in a defined space and orientation.

 

Combining different techniques in molecular biology and biochemistry we explore the possibility to perform chemical modification on plant viruses. We have conducted chemical modification on the isodiametric VLPsof Maize rayado fino (MRFV) and Cucumber mosaic virusesand the flexuous Lolium latent virus (LoLV) virions.

 

 

 

The fluorescently labelled particles, analyzed by SDS-PAGE and by biotinylation assay showed the feasibility of these reactive amino acids to be used in more advanced conjugation chemistries.

 

 

Figure legend: A protein structure prediction of wild-type (wt)-MRFV-CP showing reactive cysteine amino acids (indicated by arrows). A T=3 ribbon model of isometric VLPs showing the sulfhydryl reactive chemistry for (A) biotin labeling and (B) fluorescein-5-maleimide labeling.

 

 

Reference

Natilla, A, Hammond, RW. Analysis of the solvent accessibility of cysteine residues on maize rayado fino virus virus-like particles produced in Nicotiana benthamiana plants and cross-linking of peptides to VLPs - J Vis Exp. 2013 Feb 14;(72). pii: 50084. doi: 10.3791/50084