1SQ3:
reference: Crystal structures of a tetrahedral open pore ferritin from the hyperthermophilic archaeon Archaeoglobus fulgidus., Johnson E, Cascio D, Sawaya MR, Gingery M, Schroder I, Structure. 2005 Apr;13(4):637-48. PMID: 15837202

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