PHOTOPHYSICS OF RHODOPSIN AND BACTERIORHODOPSIN

视紫红质和细菌视紫红质的光物理学

• 批准号: 2177488
• 负责人: ROBERT Richards BIRGE
• 金额: $ 18.06万
• 依托单位: SYRACUSE UNIVERSITY AT SYRACUSE
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 1997-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2177488
• 关键词: analog; animal tissue; bacteriorhodopsins; biomedical equipment development; biophysics; calorimetry; chemical binding; chromophore; computer program /software; computer simulation; conformation; infrared spectrometry; interferometry; lasers; mathematical model; microwave spectrometry; molecular dynamics; photochemistry; photoelectron spectrometry; photon absorptiometry; protein structure function; quantum chemistry; retinaldehyde; rhodopsin; visual phototransduction

Rhodopsin, the protein responsible for converting light into an optic nerve impulse, and bacteriorhodopsin, the light transducing protein of the purple membrane of Halobacterium halobium, have significantly different biological roles. Nevertheless, natural selection has converged on very similar designs for both proteins, and these similarities have prompted comparative experimental and theoretical studies. The lack of high resolution X-ray structural data has precluded precise assignment of the tertiary structure of either protein, and hence our knowledge of the binding sites and the primary events is based on indirect analyses of chemical and spectroscopic data. Despite a number of important advances during the past decade much remains to be understood and a number of interesting experimental paradoxes remain unexplained. The nature of the chromophore binding sites and the nature of the primary photochemical events of rhodopsin and bacteriorhodopsin will be studied by using spectroscopic and theoretical techniques. The goals are to understand the photophysical properties of the bound chromophores and how the proteins mediate the photochemical properties of the bound chromophores. The principal experimental methods to be used in these studies include two-photon spectroscopy, Stark effect spectroscopy, Fourier transform near infra-red spectroscopy, microwave spectroscopy, pulsed laser photocalorimetry, and time-resolved photovoltaic spectroscopy. The theoretical methods include semiempirical molecular orbital theory and molecular dynamics theory. In addition, we will seek to answer the following specific questions: (1) To what extent does water participate in mediating the photochemical properties of the bound chromophores in both proteins? (2) What is the origin of the fast photoelectric signal that is generated during the primary photochemical events in rhodopsin and bacteriorhodopsin? (3) Can we observe and use protein-chromophore charge transfer bands to help analyze the nature of the protein chromophore interactions within the protein binding site? (4) What is the origin of the strong microwave absorptivity of bacteriorhodopsin and the origin of the M - bR microwave difference spectrum? (5) What is the nature of energy storage in the primary events of rhodopsin and bacteriorhodopsin? (6) Are there charged amino acids near the ring of the chromophore in bacteriorhodopsin? Furthermore, we will seek to develop a new method of collecting two-photon spectra of photochemically labile biological molecules based on Fourier transform optical techniques.

视紫红质，负责将光转化为光学的蛋白质 神经冲动和细菌视紫红质，光传导蛋白 盐杆菌的紫色膜，具有显着的 不同的生物学作用。 尽管如此，自然选择已经 两种蛋白质的设计非常相似，并且这些 相似之处促使实验和理论进行比较 研究。由于缺乏高分辨率 X 射线结构数据 排除了三级结构的精确分配 蛋白质，因此我们对结合位点和主要的了解 事件基于化学和光谱的间接分析 数据。 尽管在过去十年中取得了许多重要进展 还有很多有待理解和一些有趣的实验 悖论仍然无法解释。 发色团结合的性质 视紫红质主要光化学事件的位点和性质 和细菌视紫红质将通过使用光谱和 理论技术。 目标是了解光物理 结合发色团的特性以及蛋白质如何介导 结合发色团的光化学性质。 校长 这些研究中使用的实验方法包括双光子 光谱、斯塔克效应光谱、傅里叶变换近 红外光谱、微波光谱、脉冲激光 光量热法和时间分辨光伏光谱。 这 理论方法包括半经验分子轨道理论和 分子动力学理论。 此外，我们将寻求回答 以下具体问题：（1）水在多大程度上参与 介导结合发色团的光化学性质 两种蛋白质？ (2) 快速光电信号的起源是什么 它是在视紫红质的初级光化学事件期间产生的 和细菌视紫红质？ (3)我们可以观察和使用蛋白质发色团吗 电荷转移带有助于分析蛋白质的性质 蛋白质结合位点内的发色团相互作用？ (4) 什么是 细菌视紫红质强微波吸收性的起源 M-bR微波差谱的起源？ (5) 什么 是视紫红质初级事件中能量储存的本质， 细菌视紫红质？ (6) 环附近是否有带电氨基酸 细菌视紫红质中的发色团？此外，我们将寻求 开发一种收集双光子光谱的新方法 基于傅里叶变换的光化学不稳定生物分子 光学技术。