4BVN:
reference: The 2.1 A Resolution Structure of Cyanopindolol-Bound beta1-Adrenoceptor Identifies an Intramembrane Na+ Ion that Stabilises the Ligand-Free Receptor., Miller-Gallacher JL, Nehme R, Warne T, Edwards PC, Schertler GF, Leslie AG, Tate CG, PLoS One. 2014 Mar 24;9(3):e92727. doi: 10.1371/journal.pone.0092727. eCollection, 2014. PMID: 24663151

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