Bacteriorhodopsin: The influence of the cyclohexene-ring methyls
作者:J. M. L. Courtin、L. Verhagen、P. L. Biesheuvel、J. Lugtenburg、R. L. van der Bend、K. van Dam
DOI:10.1002/recl.19871060402
日期:——
of the modified bacteriorhodopsins were much lower than those of the native system. UV-Vis and 1H NMR data support a planar 6-s-transconformation for the demethylated retinals in solution rather than a twisted 6-s-cis conformation (torsion angle 40-60°) as found in retinal. This explains the lower opsin shift and the better fit of these demethylated retinals in bacteriorhodopsin's binding site, which
四个环去甲基化视网膜,即。1,1,5'-tridemethylretinal,1,1'-didemethylretinal,1,5-didemethylretinal和1-didemethylretinal已通过新的简单方案合成。研究了这些修饰的视网膜,其质子化的席夫碱和相应的细菌视紫红质的特性,并将其与天然系统进行了比较。还对这些细菌视紫红质类似物的质子泵效率进行了测试。发现缺少5-甲基的类似物的质子泵活性大大降低。总体而言,修饰的细菌视紫红质的视蛋白移位远低于天然系统。UV-Vis和1 H NMR数据支持平面6 -s-trans溶液中去甲基化的视网膜的构象,而不是视网膜中扭曲的6 -s-顺式构象(扭转角40-60°)。这解释了视紫红质视蛋白移位较低,且这些去甲基化的视网膜更适合细菌视紫红质的结合位点,而细菌视紫红质的结合位点以其天然形式包含6 -s-反生色团。
5-Demethylretinal and its 5-2H, 7-2H2 and 5,7-2H2 isotopomers. Synthesis, photochemistry and spectroscopy
作者:M. B. Spijker-Assink、C. Winkel、G. S. Baldwin、J. Lugtenburg
DOI:10.1002/recl.19881070304
日期:——
All-trans-5-demethylretinal and its5-2H, 7-2H and 5,7-2H2isotopomers have been synthesized by means of a new and simple scheme. Using photochemistry, the 9-, 11- and 13-cis, as well as the 9,13- and 11,13-di-cis isomers, were obtained. The structures were established by means of 1H NMR spectroscopy.