1QX3:
reference: Conformational restrictions in the active site of unliganded human caspase-3., Ni CZ, Li C, Wu JC, Spada AP, Ely KR, J Mol Recognit 2003 May-Jun;16(3):121-4. PMID: 12833566

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