Fig. 2: The PCV-1 protrusion domain forms the homodimer interface.

a The PCV-1 P domain shown in cartoon form, residues close to the interface are shown in stick form. Dashed lines denote the regions occupied by the hypervariable loop for which there is no density. b α7 from each subunit form a hydrophobic interface at the tip of the P domain. c β7 from each subunit swaps into the opposing P domain forming an extended hydrogen bond network in a 3-standed β-sheet.