Importance of bound divalent cations to the tyrosine deprotonation during the photocycle of bacteriorhodopsin.
Importance of bound divalent cations to the tyrosine deprotonation during the photocycle of bacteriorhodopsin.
复制标题
细菌视紫红质光循环过程中结合的二价阳离子对酪氨酸去质子化的重要性。
DOI：
10.1073/pnas.82.11.3662
复制
发表时间：
1985
影响因子：
11.1
通讯作者：
M. El
中科院分区：
文献类型：
--
作者：
P. Dupuis;T. Corcoran;M. El
研究了去离子和酸化的细菌视紫红质（蓝膜）在光循环过程中在297 nm处发生的瞬态吸收变化。与紫膜的光循环过程中发生的情况相反，对于蓝膜，仅存在对应于视网膜发色团的反式-顺式异构化的快速吸收增加;没有观察到归因于酪氨酸去质子化的缓慢上升。向去离子膜中添加不同的盐可以恢复原始颜色，并在光循环期间引起酪氨酸去质子化。这表明，阳离子的存在是必需的酪氨酸的去质子化，因为它是为去质子化的亚视黄基席夫碱。这些结果进行了讨论，最近提出的阳离子模型中观察到的去质子化过程中的光循环的细菌视紫红质。
The transient absorption changes occurring at 297 nm during the photocycles of the deionized and acidified bacteriorhodopsins (blue membranes) were studied. As opposed to what happens during the photocycle of the purple membrane, for the blue membranes only the fast absorption increase corresponding to trans-cis isomerization of the retinal chromophore is present; the slow rise attributed to the tyrosine deprotonation is not observed. The addition of different salts to the deionized membrane restores the original color and causes a tyrosine deprotonation during the photocycle. This suggests that the presence of cations is required for the deprotonation of tyrosine as it is for the deprotonation of the retinylidene Schiff base. These results are discussed in terms of the recently proposed cation model for the observed deprotonation processes in the photocycle of bacteriorhodopsin.