5L1V:
reference: The Cytochrome P450-Catalyzed Oxidative Rearrangement in the Final Step of Pentalenolactone Biosynthesis: Substrate Structure Determines Mechanism., Duan L, Jogl G, Cane DE, J Am Chem Soc. 2016 Sep 2. PMID: 27588339

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