Conformational analysis of a retinal Schiff base chromophore in proteorhodopsin by Raman optical activity
Conformational analysis of a retinal Schiff base chromophore in proteorhodopsin by Raman optical activity
复制标题
通过拉曼光学活性对原视紫红质中视网膜希夫碱发色团进行构象分析
DOI：
10.1021/acs.jpclett.1c02552
复制
发表时间：
2021
影响因子：
4.4
通讯作者：
M.
中科院分区：
文献类型：
--
作者：
Fujisawa;T.;Nishikawa;K.;Tamogami;J.;Unno;M.
利用拉曼光学活性(ROA)研究了全球分布的水生细菌光驱动质子泵--绿色光吸收蛋白视紫红质中视网膜Schiff碱色团的构象。ROA光谱主要由生色团的负振动带组成，而氢离面模式(960 cm-1)是唯一的正振动带。这一明显的光谱特征不是用视网膜席夫碱的扭曲结构解释的，而是用β-紫罗兰酮环侧的多烯链弯曲出平面的结构模型再现的。弯曲的发色团结构可能与质子耦合，通过与β-紫罗兰酮环接触的第六螺旋的运动来泵送质子。
Raman optical activity (ROA) spectroscopy was used to study the conformation of the retinal Schiff base chromophore in green-light-absorbing proteorhodopsin, which is a globally distributed light-driven proton pump of aquatic bacteria. The ROA spectrum consisted mostly of the negative vibrational bands of the chromophore, while the hydrogen out-of-plane mode (at 960 cm–1) appeared as the sole positive band. This distinct spectral feature was not explained by the twisted structure of the retinal Schiff base but was reproduced by the structural model in which the polyene chain on the β-ionone ring side was bent out-of-plane. The bent chromophore structure potentially couples with proton pumping through the motion of the sixth helix in contact with the β-ionone ring.