Time Resoved Vibration Spectrocopy of Functioning Substrate-Bound Nitrogenase

无机化学、生物无机化学和金属有机化学项目的这一奖项支持加州大学河滨分校的Stephen P.Cramer教授通过使用时间分辨红外(TR-IR)光谱和相关技术阐明固氮酶的原子水平机制。固氮酶生物化学和TR-IR光谱的最新进展为确定大气中氮气生物还原为土壤中可用于植物生长的氨的化学基础提供了前景。其具体目的是：1)利用TR-IR光谱分析MoFe固氮酶在周转条件下的底物结合形式。2)红外动力学，探讨MoFe固氮酶的作用机制，特别是关键氨基酸残基和同位柠檬酸在周转过程中的变化。3)太赫兹(Far-IR)光谱研究与MoFe：Fe蛋白质络合物形成相关的构象模式。功能固氮酶的IR动力学将被用来探索诸如质子转移、蛋白质构象随耗能的ATP水解的变化以及酶周转过程中固氮酶蛋白质复合体的形成和解离等机制。这项研究的更广泛影响包括：1)通过使用加州大学戴维斯分校、犹他州立大学、中佛罗里达大学和劳伦斯·伯克利国家实验室的最先进设施以及ALS、伯克利和杰斐逊实验室的同步辐射仪器，促进教学、培训和学习。2)建立一个方案，通过暑期实习让代表不足的群体(族裔和残疾人)在高中一级参与进来。3)通过建立独特的科学仪器(TR-IR低容量仪器)和广泛的合作，为研究和教育建立基础设施。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports Professor Stephen P. Cramer at the University of California at Riverside to elucidate the atomic-level mechanism of the nitrogenase enzyme by using time-resolved infra-red (TR-IR) spectroscopy with related techniques. Recent advances in nitrogenase biochemistry and TR-IR spectroscopy offer the prospect of determining the chemistry underpinning biological reduction of nitrogen gas in the atmosphere to ammonia available in soils for plant growth. Specific aims are to use: 1) TR-IR spectroscopy to speciate substrate bound forms of MoFe nitrogenase under turnover conditions. 2) IR kinetics to probe the mechanism of MoFe nitrogenase, particularly with regard to changes in key amino-acid residues and homocitrate during turnover. 3) Terahertz (Far-IR) spectroscopy to study the conformation modes associated with MoFe:Fe protein complex formation. IR kinetics of functioning nitrogenase will be used to probe mechanistic aspects such as proton translocation, changes in the protein conformational concomitant with the energy consuming ATP hydrolysis, and formation and dissociation of the nitrogenase protein complex during enzyme turnover. The broader impacts of this research include: 1) Promoting teaching, training and learning by using state of the art facilities at the University of California Davis, Utah State University, the University of Central Florida and Lawrence Berkeley National Laboratory as well as synchrotron radiation instrumentation at the ALS, Berkeley and Jefferson Laboratory. 2) Establishing a program to involve underrepresented groups (ethnic and disabled) at the high school level through summer internships. 3) The establishment of infrastructure for research and education through both the establishment of unique scientific instrumentation (the TR-IR low volume apparatus) and wide ranging collaborations.