6QKJ:
reference: An Alternative Active Site Architecture for O2 Activation in the Ergothioneine Biosynthetic EgtB from Chloracidobacterium thermophilum., Stampfli AR, Goncharenko KV, Meury M, Dubey BN, Schirmer T, Seebeck FP, J Am Chem Soc. 2019 Mar 18. doi: 10.1021/jacs.8b13023. PMID: 30883103

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