4EK1:
reference: Double electron-electron resonance shows cytochrome P450cam undergoes a conformational change in solution upon binding substrate., Stoll S, Lee YT, Zhang M, Wilson RF, Britt RD, Goodin DB, Proc Natl Acad Sci U S A. 2012 Aug 7;109(32):12888-93. Epub 2012 Jul 23. PMID: 22826259

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