2XQ5:
reference: Structural basis of open channel block in a prokaryotic pentameric ligand-gated ion channel., Hilf RJ, Bertozzi C, Zimmermann I, Reiter A, Trauner D, Dutzler R, Nat Struct Mol Biol. 2010 Nov;17(11):1330-1336. Epub 2010 Oct 31. PMID: 21037567

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