3ES9:
reference: Structure and function of an NADPH-cytochrome P450 oxidoreductase in an open conformation capable of reducing cytochrome P450., Hamdane D, Xia C, Im SC, Zhang H, Kim JJ, Waskell L, J Biol Chem. 2009 Apr 24;284(17):11374-84. Epub 2009 Jan 26. PMID: 19171935

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