5E59:
reference: drFrnE Represents a Hitherto Unknown Class of Eubacterial Cytoplasmic Disulfide Oxido-Reductases., Bihani SC, Panicker L, Rajpurohit YS, Misra HS, Kumar V, Antioxid Redox Signal. 2018 Feb 1;28(4):296-310. doi: 10.1089/ars.2016.6960. Epub, 2017 Oct 16. PMID: 28899103

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