2I9H:
reference: NMR solution structure of the reduced form of thioredoxin 1 from Sacharomyces cerevisiae., Pinheiro AS, Amorim GC, Netto LE, Almeida FC, Valente AP, Proteins. 2008 Feb 1;70(2):584-7. PMID: 17932921

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