ASSIGNMENT AND INTERPRETATION OF HYDROGEN OUT-OF-PLANE VIBRATIONS IN THE RESONANCE RAMAN-SPECTRA OF RHODOPSIN AND BATHORHODOPSIN
ASSIGNMENT AND INTERPRETATION OF HYDROGEN OUT-OF-PLANE VIBRATIONS IN THE RESONANCE RAMAN-SPECTRA OF RHODOPSIN AND BATHORHODOPSIN
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DOI：
10.1021/bi00531a028
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发表时间：
1982-01-01
期刊：
影响因子：
2.9
通讯作者：
MATHIES, R
中科院分区：
文献类型：
--
作者：
EYRING, G;CURRY, B;MATHIES, R
本文利用共振拉曼研究了视色素类似物再生过程中的氢面外（HOOP）振动，并对视紫红质、异视紫红质和深视紫红质的HOOP振动进行了归属。低温77 ℃K光稳态实验表明，独特的853-，875-和921-cm-1线的视紫红质是由于孤立的14，10和11 HOOP摆动模式，分别。12 HOOP摆动无法直接观察到，但必须位于830-860-cm-1区域，这是这种振动的异常低频率。室温快速流动实验类似地证明视紫红质中的969-cm-1谱线是由于偶联的C11 H = C12 H A2 HOOP。异视紫红质中的959-cm-1线归因于C7 H = C8 H Au HOOP。对于视紫红质，12-D取代的11 HOOP的小位移（921 → 922）。916 cm-1）清楚地表明11和12 HOOP仅弱耦合。这与在视紫红质、异视紫红质和全反式视网膜中观察到的这些wags之间的强耦合形成鲜明对比。模型描绘了11-trans-retinal生色团在bathorhodopsin扭曲链单键是不够的，以考虑这些新的观察。与以前的结果一起，这表明，bathorhodopsin发色团具有扭曲的11-反式结构，其通过与视蛋白残基的相互作用（推测为静电）在C12附近被显著扰动。根据电子振动理论对视紫红质和视紫红质HOOP强度的解释表明，这些色素的激发态通过λ的初始面外畸变而弛豫。10.degree.沿着增强的HOOP坐标。因为在模型化合物中看不到强烈的HOOP模式，所以这些面外畸变是由视蛋白引起的。HOOP强度提供了蛋白质如何引导视紫红质和视紫红质发色团的激发态弛豫的直接指示。
Resonance Raman studies of visual pigment analogues regenerated with 10-D, 10,11-D2, 11-D, 11,12-D2, 12-D, 15-D and 20,14-D4 isotopic derivatives of retinal were used to assign the intense hydrogen out-of-plane (HOOP) vibrations in the spectra of rhodopsin, isorhodopsin, and bathorhodopsin. Low temperature 77.degree. K photostationary steady-state experiments show that the unique 853-, 875-, and 921-cm-1 lines of bathorhodopsin are due to isolated 14, 10 and 11 HOOP wagging modes, respectively. The 12 HOOP wag could not be directly observed but must lie in the 830-860-cm-1 region, an unusually low frequency for this vibration. Room temperature rapid-flow experiments similarly demonstrate that the 969-cm-1 line in rhodopsin is due to the coupled C11H.dbd.C12H A2 HOOP. The 959-cm-1 line in isorhodopsin is attributed to a C7H.dbd.C8H Au HOOP. For bathorhodopsin, the small shift of the 11 HOOP wag with 12-D substitution (921 .fwdarw. 916 cm-1) clearly indicates that the 11 and 12 HOOPs are only weakly coupled. This contrasts sharply with the strong coupling observed between these wags in rhodopsin, isorhodopsin, and all-trans-retinal. Models depicting an 11-trans-retinal chromophore in bathorhodopsin with twists about chain single bonds are insufficient to account for these new observations. Taken together with previous results, this indicates that the bathorhodopsin chromophore has a twisted 11-trans structure that is significantly perturbed near C12 by its (presumably electrostatic) interaction with an opsin residue. Interpretation of the rhodopsin and bathorhodopsin HOOP intensities according to vibronic theory shows that the excited states of these pigments relax by an initial out-of-plane distortion of .apprx. 10.degree. along the enhanced HOOP coordinates. Because intense HOOP modes are not seen in model compounds, these out-of-plane distortions are induced by opsin. The HOOP intensities provide a direct indication of how the protein guides the excited-state relaxation of the rhodopsin and bathorhodopsin chromophores.