A model depicting formation of the mature capsid trimer interface upon protease cleavage.

<p>(A) Structure model of the CA-SP1-NC protein was composed using the CA model derived from molecular docking (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1002886#ppat-1002886-g002" target="_blank">Fig. 2</a>), combined with a SP1 partial helix (hypothetical) and the NC model (PDB 1f6u). The linker between CA-CTD and SP1 is in close contact with the MHR region of CA-CTD (in red). Scissors point to the two protease cleavage sites, Site 1 and Site 2, respectively. (B) Superposition of the CA hexameric structural models from CA-SP1-NC (blue) and CA structures (yellow) viewed from top and side. The two CA models were aligned at the CA-NTD region (light blue). (C) Comparison of the trimer interfaces (red-dashed circles) between CA-SP1-NC (blue) and CA structures (yellow).