Pettei M J, Yudd A P, Nakanishi K, Henselman R, Stoeckenius W
Biochemistry. 1977 May 3;16(9):1955-9. doi: 10.1021/bi00628a031.
The purple membrane of Halobacterium halobium contains the protein bacteriorhodopsin which resembles the visual pigment, rhodopsin, in many aspects. The isomeric configurations of its chromophore, retinal, were studied by a combination of methylene chloride extraction and analysis by high-pressure liquid chromatography. The light-adapted form bR570LA yields solely all-trans-retinal, while the dark-adapted form of bacteriorhodopsin, bR560DA, yields a mixture of 13-cis and all-trans with a ratio of similar to 1;1. The photointermediate M412 in a membrane modified by ether at high NaCl concentration also yields an approximately 1:1 mixture of 13-cis-and all-trans-retinals, while a similar M405 species produced by illumination in 2 M guanidine hydrochloride at high pH yields mainly 13-cis-retinal. These results indicate that the photochemical cycle of bR570LA may involve an isomerization of the retinal chromophore from the all-trans to the 13-cis form.
嗜盐菌的紫膜含有细菌视紫红质蛋白，该蛋白在许多方面类似于视觉色素视紫红质。通过二氯甲烷萃取和高压液相色谱分析相结合的方法，研究了其发色团视黄醛的异构构型。光适应形式bR570LA仅产生全反式视黄醛，而细菌视紫红质的暗适应形式bR560DA产生13-顺式和全反式的混合物，比例约为1:1。在高NaCl浓度下经乙醚修饰的膜中的光中间体M412也产生约1:1的13-顺式和全反式视黄醛混合物，而在高pH值的2 M盐酸胍中光照产生的类似M405物种主要产生13-顺式视黄醛。这些结果表明，bR570LA的光化学循环可能涉及视黄醛发色团从全反式到13-顺式形式的异构化。
