FEMTO/PICOSECOND LASER SPECTROSCOPY OF RHODOPSINS

视紫红质的飞秒/皮秒激光光谱

• 批准号: 3305867
• 负责人: GEORGE H ATKINSON
• 金额: $ 29.79万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-05-08 至 1995-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3305867
• 关键词: Raman spectrometry; animal extract; chemical structure function; chemical synthesis; conformation; electronic spectra; fluorescence spectrometry; intermolecular interaction; laser spectrometry; method development; photochemistry; protein engineering; retinaldehyde; rhodopsin; synthetic protein; time resolved data; visual phototransduction; vitamin analog

DESCRIPTION: (Adapted from investigator's abstract) Visual processes in both vertebrates and invertebrates are initiated by the photo-isomerization of retinal chromophore in the trans-membrane protein, rhodopsin. During the initial molecular events occurring within femto/picoseconds, such isomerizations ( and resultant charge separation) efficiently stores the incident light energy via chromophore-protein interactions with the surrounding protein. This storage of energy is a prerequisite for later steps in the visual cascade involving protein-protein interactions such as the binding of a G-protein (tansducin) at the rhodopsin surface. The proposed research examines the femto/picosecond photochemistry of retinal in room temperature rhodopsin in order to elucidate: (i) light- induced structural changes in the chromophore itself and (ii) retinal- protein interactions by which different retinal conformations selectively interact with the surrounding protein. The molecular mechanism by which both phenomena participate and/or an correlated with the primary photochemical events to store and transduce absorbed light energy will be studied. Samples to be examined include bovine rhodopsin (prepared with both native lipids and synthetic detergents) and artificial rhodopsin pigments synthesized by replacing the native chromophore with chemically- modified retinals. Femto/picosecond laser techniques will be used to measure changes in electronic states by transient absorption and fluorescence spectroscopy as well as changes in the polyene structure of retinal by time-resolved resonance Raman scattering. The proposed research program thereby combines femto/picosecond laser spectroscopy with advance chemical methodologies in polyene synthesis and the preparation of artificial rhodopsin pigments. In a corollary activity, the overall influence of the primary retinal and chromophore-protein events on protein-protein interactions such as G- protein binding will be explored through a collaboration in which with the fast dynamical results are correlated with G-protein activation and surfaced binding properties of selected rhodopsin samples.

描述：（改编自研究者摘要） 脊椎动物和无脊椎动物都是由光异构化引发的 视网膜色素团的跨膜蛋白，视紫红质。 期间 在飞秒/皮秒内发生的初始分子事件，例如 异构化（和所得的电荷分离）有效地储存了 通过发色团-蛋白质相互作用的入射光能 周围的蛋白质 这种能量的储存是以后的先决条件。 视觉级联中涉及蛋白质-蛋白质相互作用的步骤 G蛋白（transducin）在视紫红质表面的结合。 拟议的研究检查了飞秒/皮秒光化学的 在室温视紫红质中的视网膜，以阐明：（i）光- 在发色团本身中诱导的结构变化和（ii）视网膜- 不同的视网膜构象选择性地 与周围的蛋白质相互作用。 的分子机制 这两种现象都参与和/或相关的主要 光化学事件来储存和吸收光能， 研究了 待检查的样品包括牛视紫红质（用 天然脂质和合成洗涤剂）和人工视紫红质 通过用化学方法取代天然发色团合成的颜料， 改良的视网膜 飞秒/皮秒激光技术将用于测量 电子态的瞬态吸收和荧光光谱， 以及通过时间分辨的 共振拉曼散射。 该研究计划结合了 飞秒/皮秒激光光谱学与先进的化学方法 多烯合成及人工视紫红质色素的制备。 在一个必然的活动中，原发性视网膜和 蛋白质-蛋白质相互作用的发色团-蛋白质事件，例如G- 蛋白质结合将通过与 快速动力学结果与G蛋白激活相关， 所选视紫红质样品的表面结合性质。