4ZIB:
reference: Probing the active site tryptophan of Staphylococcus aureus thioredoxin with an analog., Englert M, Nakamura A, Wang YS, Eiler D, Soll D, Guo LT, Nucleic Acids Res. 2015 Dec 15;43(22):11061-7. doi: 10.1093/nar/gkv1255. Epub, 2015 Nov 17. PMID: 26582921

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