2QIR:
reference: Enzyme structural plasticity and the emergence of broad-spectrum antibiotic resistance., Maurice F, Broutin I, Podglajen I, Benas P, Collatz E, Dardel F, EMBO Rep. 2008 Apr;9(4):344-349. Epub 2008 Feb 22. PMID: 18292754

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