Retinoids and related compounds. Part 26. Synthesis of (11Z)-8,18-propano- and methano-retinals and conformational study of the rhodopsin chromophore†
作者:Akimori Wada、Masako Tsutsumi、Yuka Inatomi、Hiroo Imai、Yoshinori Shichida、Masayoshi Ito
DOI:10.1039/b104394n
日期:——
In order to clarify the conformation of the chromophore in rhodopsin, especially the effect of the torsional angle around the C6–C7 single bond on the CD spectrum, 8,18-propano- and methano-retinal 4 and 5 were prepared via the palladium-catalyzed coupling reaction of vinyl triflates derived from bicyclic ketones 10 and 27 with methyl (E)-3-(trimethylstannyl)but-2-enoate. In a binding experiment with bovine opsin, retinal analogs 4 and 5 afforded the new rhodopsin analogs. Although the opsin shifts of these pigments were similar to that of the native rhodopsin, CD spectra exhibited the characteristic feature owing to the locked structures of retinal
analogs. This fact strongly indicates that the CD spectra were significantly influenced by the torsional angles around the 6–7 and 8–9 single bonds of the chromophore in the protein.
为了弄清视网膜素中发色团的构象,特别是围绕 C6-C7 单键的扭转角对 CD 光谱的影响,我们通过钯催化双环酮 10 和 27 衍生的乙烯基三甲酸酯与 (E)-3-(trimethylstannyl)but-2-enoate 甲酯的偶联反应,制备了 8,18-丙基和甲基视网膜素 4 和 5。在与牛视网膜蛋白的结合实验中,视网膜类似物 4 和 5 得到了新的视网膜蛋白类似物。虽然这些色素的视紫红质偏移与原生视紫红质相似,但由于视网膜类似物的锁定结构,它们的 CD 光谱呈现出特有的特征。这一事实有力地表明,CD 光谱受到蛋白质中发色团 6-7 和 8-9 单键周围扭转角的显著影响。