3S9V:
reference: Insights into diterpene cyclization from structure of bifunctional abietadiene synthase from Abies grandis., Zhou K, Gao Y, Hoy JA, Mann FM, Honzatko RB, Peters RJ, J Biol Chem. 2012 Feb 24;287(9):6840-50. Epub 2012 Jan 4. PMID: 22219188

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