title: Modeling the resonance Raman spectrum of a metarhodopsin: implications for the color of visual pigments.
abstract: Resonance Raman spectra of an invertebrate rhodopsin are reported. The spectrum of squid acid metarhodopsin is compared with the spectra of model compounds of the retinylidene chromophore in the all-trans conformation. Correlations made between acid metarhodopsin and these crystalline model compounds with known x-ray structures indicate that the chromophore in this intermediate is an all-trans protonated Schiff base. The data suggest a mechanism for the red shift in rhodopsin.
mesh_terms: D049832:Decapodiformes; D007526:Isoelectric Point; D008968:Molecular Conformation; D012168:Retinal Pigments; D012243:Rhodopsin; D012545:Schiff Bases; D013059:Spectrum Analysis, Raman; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D012168:Retinal Pigments; D012545:Schiff Bases; D012243:Rhodopsin