MODELS OF THE PHOTOSYNTHETIC WATER OXIDATION ENZYME

光合水氧化酶的模型

• 批准号: 3295927
• 负责人: GEORGE CHRISTOU
• 金额: $ 12.51万
• 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 1991-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3295927
• 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.

金属最重要的生物学作用 锰（Mn）是催化水的Mn酶 在光合器官内氧化成分子氧（O2）， 高等植物和藻类。 阐明结构和机制 这一系统的作用代表了一个强电流区 生物化学界的活动。 允许详细 在原子水平上获得关于Mn位点的信息， 小分子量聚合物的可获得性将是高度期望的， Mn络合物作为天然单元的模型。 这样的模型 将是非常宝贵的，以协助epr和EXAFS研究的 酶，并允许获得机械细节，如 底物结合的可能模式和随后的 衬底氧化 没有令人满意的模型， 然而，他们的综合和研究代表了主要的 这个研究项目的重点。 初步结果描述了 与酶显著相关的第一Mn络合物 现在已经合成了。 这些物种已经展示了几个 与已知特性和结构雅阁的特征 酶上可用的参数。 EXAFS、EPR和固态 磁研究建议进一步确定 可用的合成物种与 天然Mn位。 该计划的合成扩展将寻求 修饰的结构，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。 这些材料的可用性还允许 研究底物结合的可能性， 实验室条件下的水氧化反应，以及 阐明的机制的细节和中间体， 催化循环 因此，拟议的方案代表了一个 这是目前正在进行的 对这一重要生物学现象的多学科研究 系统