5AHY:
reference: Structure of Halorhodopsin from Halobacterium salinarum in a new crystal form that imposes little restraint on the E-F loop., Schreiner M, Schlesinger R, Heberle J, Niemann HH, J Struct Biol. 2015 Apr 24. pii: S1047-8477(15)00082-9. doi:, 10.1016/j.jsb.2015.04.010. PMID: 25916754

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