Abstract
Several 8,16-Ethanoretinals 3 were synthesized from cyclohexanones. From the binding experiments of these analogs with apoprotein of phoborhodopsin, it was found that retinal was incorporated as 6s-trans conformation in the protein and the fine structure in absorption spectra of pigments were dependent on the coplanarity of the conjugated polyene structure in the chromophore.
Keywords: ethanoretinal, retinal analog, phoborhodopsin, chromophore, s-trans conformation