2QOP:
reference: Crystal structure of the transcriptional regulator AcrR from Escherichia coli., Li M, Gu R, Su CC, Routh MD, Harris KC, Jewell ES, McDermott G, Yu EW, J Mol Biol. 2007 Nov 30;374(3):591-603. Epub 2007 Sep 29. PMID: 17950313

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