Non-bleachable rhodopsins retaining the full natural chromophore

In another study, aimed at clarifying the role of the 12,13 twist in 11-m-retinal, the absorption properties of 14-methyl- and 13-desmethyl 14-methylretinal analogs were investigated. This proposed a twisted 12-s-cis conformation (C)2-C 3 angle set 

Studies of retinal isomers and retinal analogs in solution were useful in that they permitted to speculate on the conformation of the opsin-bound 1 l-c/s-retinal, an important problem in the stereochemistry of vision. Although there was a priori no reason to believe that the conformation of 1 l-cis-retinal when bound to opsin will be identical either to its solution conformation or to its conformation in the crystalline 

The study of visual pigment analogs serves to clarify the nature of chromophore-opsin interactions in visual pigments. Visual pigment analogs are modified retinals bound to opsins, which can be investigated by spectroscopic and biochemical methods. 

The original concept that the binding site of opsins is highly restricted allowing the binding of only the 1 l-c isomer [166] has now become obsolete. In addition to the 

The ll,12-dihydro[15-3H]retinal in which the crucial 11-ene is saturated, could be 

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