1BRX:
reference: Proton transfer pathways in bacteriorhodopsin at 2.3 angstrom resolution., Luecke H, Richter HT, Lanyi JK, Science 1998 Jun 19;280(5371):1934-7. PMID: 9632391

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