Structural roles of PCV2 capsid protein N-terminus in PCV2 particle assembly and identification of PCV2 type-specific neutralizing epitope
Fig 5
The cryo-EM structure of PCV2 VLP in complex with 3H11 Fab.
(A) The 3D reconstructed cryo-EM structure of PCV2 VLP in complex with 3H11-Fab reveals a typical T = 1 icosahedral particle fold. (B) The Fourier Shell Correlation curve of resolution for cryo-EM structure is shown. The line corresponds to the gold standard criterion for resolution estimation (FSC 0.143). (C) Segmentation and of structural model of Fab fragments binding with PCV2 VLP. The crystal structure of PCV2 VLP (PCV2-His-ΔN45) and the homology model structure of mAb-3H11-Fab were fitted into the densities of the 3D-reconstructed complex. The density maps of outer and inner shell are shown as 60% and 10% transparent surfaces, respectively, and the fitted atomic models are represented by ribbons. The densities corresponding to PCV2 VLP and 3H11 Fab fragments are colored in blue and grey, respectively. (D) Structural models of PCV2 VLP and mAb-3H11. (E) The atomic model of PCV2 VLP is colored by subunit and labeled accordingly. The heavy chain and light chain of mAb-3H11 Fab fragment are colored in red and blue, respectively. This structure clearly shows that 3H11 Fab binds to EF-loop located on the PCV2 VLP surface.