Researchers have developed fluorescent parvovirus-like particles (VLPs) by fusing truncated forms of the canine parvovirus (CPV) VP2 protein with the enhanced green fluorescent protein (EGFP). These VLPs were produced in insect cells and analyzed using fluorescence correlation spectroscopy (FCS), confocal microscopy, and electron microscopy. The study found that the non-truncated EGFP-VP2 fusion protein and the EGFP-VP2 constructs truncated by 23 and 40 amino acids were able to form VLPs, while the EGFP-VP2-14 construct, truncated by only 14 amino acids, could not. FCS analysis revealed differences in the hydrodynamic radii of the VLPs, with the EGFP-VP2-23 and EGFP-VP2-40 constructs forming VLPs with sizes similar to native CPV. The EGFP-VP2-14 construct, however, formed smaller particles that were too small to be VLPs. The study also showed that proteolysis of the EGFP-VP2 proteins could release EGFP from the VLP surface, indicating that EGFP was exposed on the surface of the VLPs. The results suggest that FCS is a valuable tool for analyzing virus assembly and provides structural information for the strategic development of parvovirus-like particles. The study highlights the importance of specific amino acid sequences in the VP2 protein for VLP formation and demonstrates the potential of using fluorescent VLPs for various applications, including vaccine development and gene delivery.Researchers have developed fluorescent parvovirus-like particles (VLPs) by fusing truncated forms of the canine parvovirus (CPV) VP2 protein with the enhanced green fluorescent protein (EGFP). These VLPs were produced in insect cells and analyzed using fluorescence correlation spectroscopy (FCS), confocal microscopy, and electron microscopy. The study found that the non-truncated EGFP-VP2 fusion protein and the EGFP-VP2 constructs truncated by 23 and 40 amino acids were able to form VLPs, while the EGFP-VP2-14 construct, truncated by only 14 amino acids, could not. FCS analysis revealed differences in the hydrodynamic radii of the VLPs, with the EGFP-VP2-23 and EGFP-VP2-40 constructs forming VLPs with sizes similar to native CPV. The EGFP-VP2-14 construct, however, formed smaller particles that were too small to be VLPs. The study also showed that proteolysis of the EGFP-VP2 proteins could release EGFP from the VLP surface, indicating that EGFP was exposed on the surface of the VLPs. The results suggest that FCS is a valuable tool for analyzing virus assembly and provides structural information for the strategic development of parvovirus-like particles. The study highlights the importance of specific amino acid sequences in the VP2 protein for VLP formation and demonstrates the potential of using fluorescent VLPs for various applications, including vaccine development and gene delivery.