46(P02) 二環性レチナールアナログを用いるレチナール蛋白質発色団のコンホメーション解析(ポスター発表の部)

概要

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In order to investigate the conformation of chromophore in retinal proteins, we synthesized the bicyclic retinal analogs (2 and 3), in which C8 and C18 or C16 positions in retinal are connected by the alkyl chains, and their interaction with opsins was studied. The enol triflates (11 and 24) readily derived from the bicyclic ketones (7 and 23), which were prepared from cyclohexanones (4 and 18) via Dieckmann type condensation and subsequent desulfonylation, were treated with methyl (E)-3-trimethylstanyl-2-butenoate in the presence of palladium diacetate to afford the coupling products. These compounds were converted to the corresponding retinal analogs (2, 14 and 3) via Wittig reaction or Emmons-Horner reaction. The binding experiments of 2, 14 and 3 with various opsins were carried out to afford the new artificial pigments. In rhodopsin, from the comparison of opsin shift values, it was substantiated that the torsional angle around the 6-7 single bond is very close to that of 8, 18-ethanoretinal having a seven membered ring. Furthermore, it was found that the retinal was incorporated as 6s-cis conformation in retinochrome, on the contrary, 6s-trans conformation in both sensoryrhodopsin and phoborhodopsin, respectively.
天然有機化合物討論会の論文
1997-07-20