6W6N:
reference: The Heme-Lys Cross-Link in Cytochrome P460 Promotes Catalysis by Enforcing Secondary Coordination Sphere Architecture., Coleman RE, Vilbert AC, Lancaster KM, Biochemistry. 2020 Jun 23;59(24):2289-2298. doi: 10.1021/acs.biochem.0c00261., Epub 2020 Jun 11. PMID: 32525655

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