MODELS OF THE PHOTOSYNTHETIC WATER OXIDATION ENZYME

光合水氧化酶的模型

• 批准号: 3295930
• 负责人: GEORGE CHRISTOU
• 金额: $ 11.8万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-02-01 至 1990-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3295930
• 关键词: biochemistry; catalyst; chemical models; chemical structure function; enzyme mechanism; manganese; oxidation; oxygen; photosynthesis; water

The most important biological role yet recognized for the metal manganese (Mn) is the Mn enzyme which catalyzes water oxidation to dioxygen (O2) within the photosynthetic apparatus of higher plants and algae. Elucidating the structure and mechanism of action of this system represents an area of intense current activity within the biochemical community. To allow detailed information on the Mn site to be obtained at an atomic level, the availability would be highly desirable of small molecular weight Mn complexes to act as models of the native unit. Such models would be invaluable to assist in epr and EXAFS studies of the enzyme, and to allow mechanistic detail to be obtained, such as possible modes of substrate binding and mechanism of subsequent substrate oxidation. No satisfactory models have been available, however, and their synthesis and study represents the primary focus of this research program. Preliminary results described how the first Mn complexes of significant relevance to the enzyme have now been synthesized. These species already display several features in accord with known properties and structural parameters available on the enzyme. EXAFS, epr and solid-state magnetic studies are proposed to further define the correspondence between available synthetic species and the native Mn site. Synthetic extensions to the program will seek to modify the structures, ligation type and oxidation levels of attainable materials to allow broader and more detailed comparisons. Availability of such materials also allows the possibility of investigating substrate binding, reproducing the water oxidation reaction under laboratory conditions, and elucidating the mechanistic detail of and intermediates during the catalytic cycle. The proposed program thus represents an essential and hitherto unavailable component of the ongoing multi-disciplinary investigation of this important biological system.

金属迄今为止公认的最重要的生物学作用 锰 (Mn) 是催化水的锰酶 光合机构内氧化成分子氧（O2） 高等植物和藻类。 阐明结构和机制 该系统的作用代表一个强电流区域 生化界内的活动。 为了让详细的 要在原子水平上获得有关 Mn 位点的信息， 小分子量的可用性将是非常理想的 锰配合物充当本机单元的模型。 此类车型 对于协助 EPR 和 EXAFS 研究将是非常宝贵的 酶，并获得机械细节，例如 底物结合的可能模式和后续机制 底物氧化。 还没有找到满意的型号， 然而，它们的合成和研究代表了主要的 本研究计划的重点。 初步结果描述了如何 第一个与酶显着相关的锰络合物 现已合成。 这些物种已经表现出几种 符合已知特性和结构的特征 酶上可用的参数。 EXAFS、epr 和固态 提出磁性研究以进一步定义 可用合成物种与 原生锰位点。 该计划的综合扩展将寻求 修改结构、连接类型和氧化水平 可获得的材料，以允许更广泛和更详细的 比较。 此类材料的可用性还允许 研究底物结合的可能性，重现 实验室条件下的水氧化反应，以及 阐明中间体的机制细节 催化循环。 因此，拟议的计划代表了 正在进行中的重要且迄今为止不可用的组成部分 对这一重要生物学领域的多学科研究 系统。