Assembly and Function of Cyanobacterial Photosystem II

光系统II （PSII）是一种至关重要但复杂的酶，它构成了支持地球上所有生命的光合机制的基础。这种酶负责利用光能从水中提取氢。整个过程导致地球上生命的食物，同时从地球大气中去除无机碳，并产生地球动物和其他异养生命形式所必需的氧气。从经济的角度来看，如果要成功地开发出用于太阳能转换的仿生设备，以产生可用的氢或氢化物作为未来电动汽车的能源，那么了解这一过程是很重要的。尽管它很重要，但对这种酶的机制的许多方面仍然知之甚少。此外，光系统II在正常运行过程中受到的损害率非常高，因此是植物的“阿喀琉斯之踵”。许多类型的植物胁迫，包括干旱，导致光系统II的快速和潜在致命的损失，因为这种损害。因此，植物必须不断地替换光系统II中受损的部分，这对生物合成提出了重要的挑战，但仍未被理解。这个研究项目正在发展对水分解机制的理解以及光系统II的高速率修复是如何完成的。该研究认为光系统II是一个分子机器，并且有可能通过使用最先进的遗传方法改变其部件来了解该机器如何运行，并使用各种信息丰富的生化和生物物理技术探测机器运行中的结果变化。本研究利用了PSII“机器”分子结构的最新结晶和可视化技术。它结合了基于结构的诱变来研究模式生物聚囊藻PCC 6803光系统II复合体的组装和功能。具体而言，该项目将解决光系统II光激活机制的假设，并将通过微阵列实验更好地定义参与修复周期的蛋白质因子。更广泛的影响：这些影响超出了直接的科学领域：1)拟议的工作将为本科生，研究生和博士后提供重要的培训机会。2)该项目将对Synechocystis微阵列的生产（按成本回报分配）和俄克拉何马州微阵列核心设施举办的讲习班产生积极影响。这些阵列服务于教学目标，并在夏季讲习班上用于教授微阵列生产和应用的原理，这些讲习班为大学和周边地区服务。3)它将允许更多的人参与俄克拉荷马州立大学最近更新的印第安人生物科学（NABS）项目。

Photosystem II (PSII) is a crucial but complex enzyme that forms the foundation of the photosynthetic machinery that supports all life on earth. This enzyme is responsible for using light energy to extract hydrogen from water. The overall process results in food for life on earth along with the removal of inorganic carbon from the earth's atmosphere and production of oxygen essential for earth's animals and other heterotrophic life forms. From an economic perspective, an understanding of this process is important if successful biomimetic devices are to be developed for such things as solar energy conversion to produce utilizable hydrogen or hydrides as an energy source to power future electric cars. Despite its importance, many aspects of the enzyme's mechanism remain poorly understood. Furthermore, photosystem II sustains very high rates of damage during its normal operation and is, thus, the 'Achilles Heel' of the plant. Many types of plant stress, including drought, result in the rapid and potentially lethal loss of photosystem II because of this damage. Plants must therefore constantly replace the damaged parts of photosystem II and this presents important biosynthetic challenges that are also still not understood.This research project is developing an understanding of the water-splitting mechanism and how the high rates of photosystem II repair are accomplished. The research takes the perspective that photosystem II is a molecular machine and that it is possible to understand how this machine operates by changing its parts using state-of-the-art genetic methods and probing the resultant changes in the machine's operation using a variety of informative biochemical and biophysical techniques. This research takes advantage of the recent crystallization and visualization of the molecular structure of the PSII 'machine'. It combines structure-based mutagenesis to study the assembly and function of the photosystem II complex in a model organism, Synechocystis PCC 6803. Specifically, this project will address hypotheses on the mechanism of photoactivation of photosystem II and will better define the protein factors participating in the repair cycle using microarray experiments.Broader Impacts: These extend beyond the immediate scientific area: 1) The proposed work will provide significant training opportunities for undergraduate students, graduate students, and postdoctoral fellows. 2) The project will have positive impact on the production of Synechocystis microarrays (distributed on a cost-return basis) and the workshops that the Oklahoma Microarray Core Facility conducts. These arrays serve teaching objectives and are being used to teach the principals of microarray production and applications in summer workshops serving the university and surrounding regions. 3) It will allow increased participation in the recently renewed Native Americans in Biological Sciences (NABS) program at Oklahoma State University.