Assembly and Function of the Cyanobacterial Photosystem II Complex

蓝藻光系统 II 复合体的组装和功能

基本信息

批准号：
1716408
负责人：
Robert Burnap
金额：
$ 79.42万
依托单位：
Oklahoma State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-07-01 至 2023-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1716408&HistoricalAwards=false
关键词：
Assembly Function Cyanobacterial Photosystem II

项目摘要

The photosystem II (PSII) complex found in plants, algae, and cyanobacteria is a chlorophyll-protein complex located in specialized internal cell membranes called thylakoids. PSII catalyzes the crucial water-splitting reaction that uses solar energy to produce the activated hydrogen required for food and energy production throughout the Earth's biosphere. At the same time, the PSII is responsible for the production of essentially all the gaseous oxygen on Earth. Despite its global importance, PSII can also be considered the "Achilles Heel" of photosynthetic organisms. This is because it is prone to damage from the very light that it uses as an energy source. Consequently, PSII is under a constant state of repair owing to this incessant light damage. The project will elucidate the poorly understood repair mechanism with a focus on the assembly of the catalytic metals necessary for oxygen evolution. In addition to the fundamental research, the project will provide extensive training opportunities for undergraduate and graduate students in in the areas of biochemistry, biophysics, and molecular genetics. Moreover, the is a large outreach component of the project that is designed to provide research opportunities for pre-service and in-service high school teachers. The project will investigate the multistep assembly of the metal cluster (Mn4CaO5) catalytic center of the PSII water-splitting complex. Recent work has revealed the migration of damaged PSII to specialized "repair zones" located in the peripheral regions of the cell. The project tests the hypotheses that (1) loss of the the Mn4CaO5 triggers the migration to repair zones and (2) the assembly of the Mn4CaO5 cluster occurs efficiently only after migration of the damaged PSII complex to these repair zones. Because light also drives Mn4CaO5 assembly, the process can be precisely controlled using flashes of light, which will allow new insights into the broad problem of metal cluster assembly in proteins. The work will use a genetically transformable cyanobacterium and an array of techniques that probe the assembly process with molecular resolution. State-of-the-art biophysical and molecular genetic techniques are being developed and utilized by the PI and collaborators. These include synthetic DNA, high-speed polarography, EPR, and FTIR techniques.

在植物，藻类和蓝细菌中发现的光系统II（PSII）复合物是一种叶绿素 - 蛋白质复合物，位于专门的内部细胞膜中，称为囊类细胞。 PSII催化了使用太阳能生产整个地球生物圈中食品和能源生产所需的活化氢的关键水分反应。同时，PSII负责地球上基本上所有的气体氧。尽管具有全球性的重要性，但PSII也可以被视为光合生物的“致命弱点”。这是因为它很容易受到用作能源的光的损害。因此，由于这种不断的光损伤，PSII处于恒定的维修状态。该项目将阐明熟悉的修复机制，重点是组装氧气进化所需的催化金属。除了基本研究外，该项目还将为生物化学，生物物理学和分子遗传学领域的本科和研究生提供广泛的培训机会。此外，该项目的大型外展部分旨在为服务前和服务中的高中教师提供研究机会。该项目将研究psii水分分解复合物的金属簇（MN4CAO5）催化中心的多步组件。最近的工作表明，受损的PSII迁移到该细胞周围区域的专门“修复区”。该项目检验了（1）MN4CAO5的损失触发迁移以修复区域，并且（2）仅在受损的PSII复合物向这些修复区域迁移后，MN4CAO5簇的组装才有效发生。由于光还驱动了MN4CAO5组件，因此可以使用光闪光来精确控制该过程，这将允许对蛋白质中金属群集组装的广泛问题进行新的见解。这项工作将使用遗传转化的蓝细菌和一系列技术，这些技术用分子分辨率探测组装过程。 PI和合作者正在开发和利用最先进的生物物理和分子遗传技术。这些包括合成DNA，高速极光学，EPR和FTIR技术。