Peptide display on a surface loop of human parvovirus B19 VP2: Assembly and characterization of virus-like particles

• Surface loop 62–75 of the structural protein VP2 of or parvovirus B19 was selected to insert a heterologous peptide F215–278.
• Chimeric protein VP2-F215–278 retains its ability to fold and self-assemble into VLPs.
• VP2 and VP2-F215–278 can also co-self-assemble into hybrid VLPs.
• Changes in colloidal stability of VP2-F215–278 VLPs indicate that peptide F215–278 is displayed on the surface of the particles.

Virus-like particles (VLPs) are valuable tools for nanotechnology and nanomedicine. These particles are obtained by the self-assembly, either in vivo or in vitro, of structural proteins of viral capsids. VLPs are excellent scaffolds for surface display of molecules. The N-termini of the structural proteins of human parvovirus B19 (B19V) have been already modified to display peptides or proteins. However, other surface-exposed elements have not been studied as potential locations for peptide display. In this research, we tested the potential of surface loop 62–75 of VP2 protein for the presentation of a 64-residue heterologous peptide. The chimeric protein was able to self-assemble in vitro into VLPs. Improved colloidal stability was observed for these particles, indicating that the peptide is on the surface of the particle. AFM analysis of the chimeric particles shows no obvious difference between the surfaces of particles assembled with VP2 and those assembled with the chimeric VP2. Our results indicate that loop 62–75 is a good candidate for heterologous peptide presentation on the surface of B19V VLPs.