SEARCH Articles Figures Tables Bacteriorhodopsin protonated Schiff base Base protonation Bases protonic Proton translocation models directly involving the Schiff base nitrogen Protonated Schiff Base (PSB Protonated Schiff-base of retinal Protonated base Protonated polyene Schiff base Retinal protonated Schiff base Retinal protonated Schiff base chromophore Schiff base protonation, hydrogen bonds