4REP:
reference: Crystal structure of 1'-OH-carotenoid 3,4-desaturase from Nonlabens dokdonensis DSW-6., Ahn JW, Kim KJ, Enzyme Microb Technol. 2015 Sep;77:29-37. doi: 10.1016/j.enzmictec.2015.05.005., Epub 2015 May 22. PMID: 26138397

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