视觉中的视网膜对比离子开关机制,通过分子模拟进行评估
Karina Martínez-Mayorga1, Michael C Pitman, Alan Grossfield
1Departments of Chemistry and Physics, University of Arizona, Tucson, AZ 85721, USA.
Journal of the American Chemical Society
|December 21, 2006
概括
罗多普辛的激活涉及一个 counterion 开关机制. 分子动力学模拟和NMR光谱表明,Glu113和Glu181都稳定了视网膜质子化希夫基在meta I状态.
科学领域:
- 生物化学 生物化学
- 分子生物学分子生物学
- 频谱学是一种光谱学.
背景情况:
- 视网烯染色体的光异构化启动了视觉级联.
- 在罗多普辛激活过程中,对抗离子开关机制对于稳定视网膜质子化希夫基 (PSB) 是至关重要的.
- 存在两种对 counterion 稳定性的模型:单独使用 Glu181,或同时使用 Glu113 和 Glu181.1.
研究的目的:
- 在罗多普辛激活中研究和区分拟议的对比离子开关模型.
- 确定Glu181和Glu113在稳定视网膜PSB中的特定作用.
主要方法:
- 微秒级,全原子分子动力学模拟罗多在脂质双层中的模拟.
- 模拟改变了Glu181.1.的质子化状态.
- 模拟的2H NMR光谱与实验数据的比较.
主要成果:
- 模拟显示了两个 counterion 开关模型的截然不同的视网膜方向.
- 对甲基组 (C5,C9,C13) 的模拟2HNMR光谱与实验数据相匹配.
- 支持了涉及Glu113和Glu181的复杂对比机制.
结论:
- Glu113 和 Glu181 协同稳定了 rhodopsin 的 I 代谢状态下的视网膜 PSB.
- 这种双重稳定在Rhodopsin的激活之前.
- 这些发现澄清了早期视觉信号转导的分子机制.
相关概念视频
Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
Channel 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,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...


