3E4C:
reference: Crystal structure of procaspase-1 zymogen domain reveals insight into inflammatory caspase autoactivation., Elliott JM, Rouge L, Wiesmann C, Scheer JM, J Biol Chem. 2009 Mar 6;284(10):6546-53. Epub 2008 Dec 30. PMID: 19117953

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