1BWL:
reference: On the active site of Old Yellow Enzyme. Role of histidine 191 and asparagine 194., Brown BJ, Deng Z, Karplus PA, Massey V, J Biol Chem 1998 Dec 4;273(49):32753-62. PMID: 9830019

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