Conformationally-flexible, reactive manganese clusters to probe possible mechanisms of oxygen-oxygen bond formation in photosystem II

构象灵活的反应性锰簇探索光系统 II 中氧-氧键形成的可能机制

基本信息

批准号：
1800105
负责人：
Michael Zdilla
金额：
$ 42万
依托单位：
Temple University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1800105&HistoricalAwards=false
关键词：
Conformationally flexible reactive manganese clusters

项目摘要

In the early stages of the development of life on earth, perhaps the most significant evolutionary breakthrough was the sunlight-driven oxidation of water to oxygen (O2) by the ancient ancestors of cyanobacteria and modern plants. These organisms discovered a way to make their own food using the virtually limitless supply of water and sunlight available near the surface of the oceans. As far as science knows, organisms have found only one way to perform this water oxidation process, and it is possible that modern plants and photosynthetic organisms are still using that same evolutionary innovation from billions of years ago, although presumably significantly evolved. The enzyme that performs this reaction is called Photosystem II, and despite the central importance of this reaction to the fields of biology and energy, many questions remain about how this enzyme works. Professor Zdilla is working to build molecular models of the enzyme active site, which is a cube-shaped cluster of metal atoms containing manganese and calcium. The working models developed by Professor Zdilla may lead to insights on how photosynthetic organisms are able to perform this important reaction. Professor Zdilla continues his community engagement of youth and adult communities through talks during the Philadelphia Science Festival and at Philadelphia elementary schools. Professor Zdilla also develops the Database of Educational Crystallographic Online Resources (DECOR), a free, downloadable source of educational materials for the study of crystallography. The primary source of cellular energy on earth is the sun, whose visible light energy is harvested by photosynthetic organisms to drive the oxidation of water to O2 and drive the concomitant reduction of carbon dioxide(CO2) to organic molecules, which are then used as fuel and as raw materials for the construction of living things. Photocatalytic water oxidation coupled to proton reduction is also an important goal for the generation of sustainable solar fuels. The enzyme responsible for the biological water oxidation reaction is photosystem II (PSII), a multi-subunit enzyme containing a tetramanganese-calcium-oxo cluster as the catalytic active site. Since enzymes are often a challenge to study directly due to their complexity, bioinorganic chemists frequently turn to biomimetic model complexes. Despite hundreds of examples of synthetic manganese oxo-cluster, very few show compelling reactivity that models PSII. Professor Zdilla and his group develop new approaches to designing biomimetic manganese clusters by prioritizing low-coordination number(to provide water binding sites) and cluster flexibility (to promote molecular rearrangement). These approaches have resulted in clusters that perform a diverse set of difficult reactions including N-N, C-H, C-N, and O=O bond making/breaking reactions, and catalytic water oxidation. This project seeks to further mechanistically investigate their molecular mechanisms, which may inform understanding of the function of the enzyme, and provide clues on how to design superior water oxidation catalysts for energy purposes. Professor Zdilla continues his community engagement of youth and adult communities through talks during the Philadelphia Science Festival and at Philadelphia elementary schools. Professor Zdilla also develops the Database of Educational Crystallographic Online Resources (DECOR), a free source of educational materials for the study of crystallography.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在地球生命发展的早期阶段，也许最重要的进化突破是阳光驱动的阳光驱动的水氧化为氧化（O2），古老的蓝细菌和现代植物的祖先。这些生物发现了一种使用几乎无限的水和阳光在海面附近可用的供水和阳光来制作食物的方法。据科学所知，生物体只找到了一种执行这种水氧化过程的方法，现代植物和光合生物可能仍在使用数十亿年前的相同进化创新，尽管大概是显着进化。执行此反应的酶被称为光系统II，尽管这种反应对生物学和能量领域的重要性至关重要，但有关该酶的工作原理仍然存在许多问题。 Zdilla教授正在努力构建酶活性位点的分子模型，该酶是一个含有锰和钙的金属原子的立方体形成簇。 Zdilla教授开发的工作模型可能会导致有关光合生物如何能够执行这一重要反应的见解。 Zdilla教授通过费城科学节和费城小学的会谈继续他的社区参与青年和成人社区。 Zdilla教授还开发了教育晶体学在线资源（Decor）的数据库，这是一种免费的，可下载的教育资料来源，用于研究晶体学研究。地球上的细胞能的主要来源是太阳，光合生物可以收获可见的光能，以将水氧化为O2氧化，并驱动二氧化碳（CO2）的同时还原到有机分子，然后将其用作燃料和燃料，用作生物构建生物的原材料。与质子还原相结合的光催化水氧化也是生成可持续太阳能燃料的重要目标。负责生物水氧化反应的酶是光系统II（PSII），这是一种含有四氨基 - 钙氧蛋白簇作为催化活性位点的多生物酶。由于酶由于其复杂性通常是直接研究的挑战，因此生物无机化学家经常转向仿生模型复合物。尽管有数百种合成锰氧簇的例子，但很少有模拟PSII的令人信服的反应性。 Zdilla教授及其小组通过优先考虑低调数（提供水结合位点）和簇灵活性（以促进分子重排）来开发新的方法来设计仿生型锰簇。这些方法导致了簇，这些簇执行了多种困难反应，包括N-N，C-H，C-N和O = O键做/断裂反应以及催化水氧化。该项目旨在进一步机械地研究其分子机制，这些机制可以告知人们对酶功能的理解，并提供有关如何为能量目的设计出色的水氧化催化剂的线索。 Zdilla教授通过费城科学节和费城小学的会谈继续他的社区参与青年和成人社区。 Zdilla教授还开发了教育晶体学在线资源（Decor）的数据库，这是晶体学研究的自由教育材料来源。该奖项反映了NSF的法定任务，并被认为值得通过基金会的知识分子优点和更广泛的影响审查标准通过评估来进行评估。