罗多普辛和异罗多普辛的兴奋状态放松路径之间的关系
Angela Strambi1, Pedro B Coto, Luis Manuel Frutos
1Dipartimento di Chimica, Università di Siena, via Aldo Moro I-53100 Siena, Italy.
Journal of the American Chemical Society
|February 28, 2008
概括
视觉色素类似物伊索罗多普辛 ( Isorhodopsin) 的光异构化过程与罗多普辛不同. 量子力学计算揭示了一个反转的反应坐标,影响其兴奋状态动态和衰变路径.
科学领域:
- 生物物理学的生物物理.
- 计算化学计算化学
- 摄影化学的使用.
背景情况:
- 像Rhodopsin这样的视觉颜料对于光线检测至关重要.
- 伊索罗多普辛是罗多普辛的结构模拟物.
- 了解它们的光异构化机制是视觉转导的关键.
研究的目的:
- 为了研究 Isorhodopsin 的兴奋状态结构和反应性.
- 为了比较Isorhodopsin与Rhodopsin的光异构化途径.
- 阐明控制这些视觉色素的衰变机制的因素.
主要方法:
- 量子力学/分子力学 (QM/MM) 的计算.
- 一开始的多配置量子化学处理.
- 分析光谱参数和反应坐标.
主要成果:
- 准确的光谱参数 (<5 kcal mol (-1) 误差) 对于伊索罗多普辛.
- 伊索罗多普辛的浅层光异构化路径,类似于罗多普辛.
- 在 Isorhodopsin 的异构化中,一个反向的反应坐标,与主导的反时钟方向扭转的 9-cis 键.
结论:
- 罗多普辛和伊索罗多普辛共享一个共同的兴奋状态潜在能量谷,但从相反的端放松.
- 明显的形交叉结构解释了色素的衰变路径.
- 该研究提供了对视觉色素功能的分子机制的见解.
相关概念视频
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
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