Time Resolved Studies of Fundamental Mechanisms in Natural Photosynthesis

自然光合作用基本机制的时间分辨研究

• 批准号: 2303743
• 负责人: Yulia Pushkar
• 金额: $ 55.09万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-15 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303743&HistoricalAwards=false
• 关键词: Time; Resolved; Studies; Fundamental; Mechanisms

With the support of the Chemistry of Life Processes Program of the Chemistry Division, Professor Yulia Pushkar of Purdue University will study the oxygen evolving complex (OEC) of photosystem II, a protein that contains manganese and calcium ions. This protein, which uses the energy of sunlight to catalyze the splitting of water molecules into protons, electrons, and oxygen molecules, provides the majority of oxygen in the Earth’s atmosphere. Application of spectroscopic methods to the study of the catalytic cycle will provide insight into the roles of the manganese and calcium ions and their protein environment in the light-driven formation of dioxygen. In the longer term, insights gained in the study of Nature's OEC in this project have the potential to enable the design of new methods for the production of energy that is CO2-neutral. The planned educational and mentoring activities range from hands-on research involvement of high school students to the training of postdoctoral fellows. New results from photosystem II research will be integrated into the biophysics curriculum that is delivered across multiple Purdue Departments at both the graduate and undergraduate levels. Professor Pushkar will create research opportunities for and advise undergraduate students including those participating in the Sloan Foundation Equitable Pathways Program Partnering in Research Mentoring for Minoritized Students in STEM (science, technology, engineering and mathematics). Professor Pushkar also actively participates in Purdue’s Women in Physics and Women in Science Programs. Research in this project will be focused upon a comprehensive vibrational analysis and time-resolved vibrational spectroscopic study of the oxygen-evolving complex (OEC) of photosystem II and its functions in the O-O bond formation. Low-frequency IR (infrared) spectroscopy is capable of detecting Mn-O vibrations in the OEC, even in the presence of the large protein. This is due to high IR activity of the Mn-O vibrations in Mn4OCa clusters. Low-frequency IR spectroscopic and isotopic labeling will be used to determine the molecular identity of the S3 state of photosystem II and its proposed isomers. Near-IR resonance Raman spectrascopy will be used in a parallel for the selective detection of Mn4OCa cluster vibrations and changes in the molecular structure of the cluster during the Kok cycle. The experimental results will be interpreted within the framework of currently available structural models of the OEC. Complementary density functional theory (DFT) calculations will be conducted to monitor the energy profile of the proposed chemical transformations in the OEC. Together this combined spectroscopic/computational study of the OEC is expected to provide new insights into the mechanism of this remarkably efficient, natural Mn-based water splitting machine.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.

在化学系生命过程化学项目的支持下，普渡大学的尤利娅·普什卡（Yulia Pushkar）教授将研究光系统II的析氧复合物（OEC），这是一种含有锰和钙离子的蛋白质，这种蛋白质利用能量。太阳光催化水分子分裂成质子、电子和氧分子，提供了地球大气中的大部分氧气。应用光谱方法研究催化循环。将深入了解锰离子和钙离子及其蛋白质环境在光驱动双氧形成中的作用。从长远来看，在该项目中对 Nature's OEC 的研究中获得的见解有可能使新的设计成为可能。计划的教育和指导活动范围从高中生的实践研究参与到博士后研究员的培训，光系统 II 研究的新成果将被纳入生物物理学课程中。 Pushkar 教授将为普渡大学多个院系的研究生和本科生提供研究机会，并为本科生提供建议，其中包括参加斯隆基金会公平途径计划合作为 STEM（科学、技术、工程）少数群体学生提供研究指导的学生。 Pushkar 教授还积极参与普渡大学的女性物理学和女性科学项目，该项目的研究重点是全面的振动分析和时间分辨振动光谱研究。光系统 II 的释氧复合物 (OEC) 及其在 O-O 键形成中的功能 低频 IR（红外）光谱能够检测 OEC 中的 Mn-O 振动，即使存在大蛋白质也是如此。由于 Mn4OCa 团簇中 Mn-O 振动的高红外活性，低频红外光谱和同位素标记将用于确定光系统 II 的 S3 态的分子身份。及其提出的异构体将同时用于选择性检测 Mn4OCa 团簇振动和 Kok 循环期间团簇分子结构的变化。实验结果将在当前的框架内进行解释。 OEC 的可用结构模型将进行互补密度泛函理论 (DFT) 计算，以监测 OEC 中拟议化学转化的能量分布。预计将为这种高效的天然锰基水分解机的机制提供新的见解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。