3IBC:
reference: Conformational similarity in the activation of caspase-3 and -7 revealed by the unliganded and inhibited structures of caspase-7., Agniswamy J, Fang B, Weber IT, Apoptosis. 2009 Aug 5. PMID: 19655253

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