title: A vibrational analysis of rhodopsin and bacteriorhodopsin chromophore analogues: resonance Raman and infrared spectroscopy of chemically modified retinals and Schiff bases.
abstract: Resonance Raman spectroscopy has been used to study chemically modified retinal analogues involving chain substitutions, ring substitutions, or Schiff-base linkages. In addition, retinal fragments and fully deuterated retinals were investigated, and infrared spectra of the four isomers of retinal were obtained. Low-frequency resonance Raman spectra are also reported for all of the isomers of retinal, for the protonated and unprotonated Schiff bases of trans-retinal, for beta-ionone, and for trans-3-dehydroretinal. Band assignments were made to specific vibrational motions, and these assignments have led to a detailed understanding of the spectral features observed in the resonance raman spectra of the retinylidene chromophore in rhodopsin and bacteriorhodopsin.
mesh_terms: D001436:Bacteriorhodopsins / Q000031:analogs & derivatives; D002338:Carotenoids; D007536:Isomerism; D007834:Lasers; D011487:Protein Conformation; D012168:Retinal Pigments; D012243:Rhodopsin / Q000031:analogs & derivatives; D012545:Schiff Bases; D013055:Spectrophotometry, Infrared; D013059:Spectrum Analysis, Raman; D013329:Structure-Activity Relationship
chemical_list: D012168:Retinal Pigments; D012545:Schiff Bases; D002338:Carotenoids; D001436:Bacteriorhodopsins; D012243:Rhodopsin