3QK1:
reference: Towards a Restriction Proteinase: Construction of a Self-Activating Enzyme., Schopfel M, Tziridis A, Arnold U, Stubbs MT, Chembiochem. 2011 Mar 8. doi: 10.1002/cbic.201000787. PMID: 21387509

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