Virus-like particles (VLPs) are composed of the structural components of virions without its genetic material, producing non-infective particles that conserve the structural properties of virions, as immunogenicity and cellular-receptor recognition. Many VLPs are fabricated in eukaryotic cells, generating fully self-assembled particles. In contrast, other VLPs can be assembled in vitro from denatured proteins. Parvovirus B19 VLPs can be produced either in eukaryotic cells or in vitro from its denatured VP2 protein. The ability of these particles to self-assemble in vitro has led our group to assemble particles composed from chimeric forms of the same protein with excellent results. We have engineered VP2 to accommodate peptides and complete proteins in surface loops as well as at the N-terminus of this protein. We hypothesized that it would be possible to co-assemble more than one chimera of VP2, producing hybrid particles with more than one heterologous function.
Herein we present the construction of VLPs carrying both, lipase and GFP domains fused to the structural VP2 protein, by co-assembly of the chimeric proteins and VP2. The resulting species displaying lipolytic activity and fluorescence were purified by SEC and analyzed by DLS and AFM to confirm its structural properties. This material is the proof of concept for the in-vitro construction of VLPs displaying different functional domains through the co-assembly of chimeric forms of VP2. These particles may help to carry catalytic or regulatory activities to target cells by selecting suitable chimeras of VP2 that produce not only those activities, but also the precise tropism.