4TX3:
reference: X-domain of peptide synthetases recruits oxygenases crucial for glycopeptide biosynthesis., Haslinger K, Peschke M, Brieke C, Maximowitsch E, Cryle MJ, Nature. 2015 Feb 9. doi: 10.1038/nature14141. PMID: 25686610

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