3TIR:
reference: A structural model for the generation of continuous curvature on the surface of a retroviral capsid., Bailey GD, Hyun JK, Mitra AK, Kingston RL, J Mol Biol. 2012 Mar 30;417(3):212-23. Epub 2012 Jan 27. PMID: 22306463

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).