Fig. 4: The hypervariable protrusion is not required for capsid assembly.

a Alignment of CP amino acid sequences of PCV-1, Pepper cryptic virus 2 (PCV-2) and the two CP sequences identified for Beet cryptic virus 2 (BCV-2). Shaded regions correspond to the unresolved regions of PCV-1 CP and positions coloured cyan correspond to > 25% identity using a 10-position rolling average. b Map of the percentage identity from the alignment to the PCV-1 protomer structure. Cyan regions have ≥ 25% identity and red regions have < 25% identity (10-position rolling average) with grey shading indicating the missing density in the PCV-1 reconstruction. c PCV-1 CP variants with protrusion deletions and TEM images of density gradient purified particles. Images show (i) WT PCV-1 CP, and two deletions of the disordered region, replaced with short linker sequences delta-link 2 (ii) and delta-link 3 (iii). Bar = 100 nm.