4JK3:
reference: Structure and Reaction Mechanism of Pyrrolysine Synthase (PylD)., Quitterer F, Beck P, Bacher A, Groll M, Angew Chem Int Ed Engl. 2013 May 29. doi: 10.1002/anie.201301164. PMID: 23720358

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