3ZIT:
reference: Tuning of thioredoxin redox properties by intramolecular hydrogen bonds., Rohr AK, Hammerstad M, Andersson KK, PLoS One. 2013 Jul 23;8(7):e69411. doi: 10.1371/journal.pone.0069411. Print 2013. PMID: 23936007

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