Synchrotron NRVS and Campus Spectroscopy of Multinuclear Fe Proteins: Nitrogenase, Hydrogenase, Methane Monoxygenase, and NO Sensor Proteins

 描述（由申请人提供）：生物Fe-S簇是含有2-8个Fe原子的纳米颗粒，这些Fe原子主要通过桥接S原子保持在一起。含有Fe-S簇的蛋白质在生命系统中起着各种各样的重要作用，包括催化化学反应， 反应，感测化学环境，向DNA发送信号和修复DNA，以及维持分子结构。我们对这一提案的主要目标集中在四个关键问题： Fe-S团簇如何与小分子反应？它们如何催化反应，它们如何作为一氧化氮和氧传感器工作，当它们分解时会发生什么？ 组装氢化酶活性中心的步骤是什么？ 较大的蛋白质环境如何影响小分子进入Fe-S位点？ Fe-S簇的化学性质如何影响蛋白质的三级结构和与DNA的相互作用？ 我们研究的预期成果包括： 关于固氮酶（固氮酶）或产氢酶（氢化酶）的催化中间体的信息 关于Fe-S簇蛋白与信号分子NO和O2反应时的反应中间体的信息，以及簇传感器转导信号以影响DNA时发生的变化 关于气体处理酶中侧链贡献和气体通道的信息，这些气体处理酶处理或抑制小分子，如N2，O2，CO和NO。 获取这些信息的方法是光谱学。 利用光解/FT-IR、NRVS和共振拉曼光谱，本工作将表征固氮酶（N2 ase）如何结合抑制剂CO，以及其与N2和更多还原中间体的复合物的结构，阐明何时以及如何在氢化酶（H2 ases）的活性位点结合抑制剂CO， 使用时间分辨光谱在各种时间尺度上，我们的目标是定义中间体和最终产品的反应NO和O2与[4Fe-4S]簇在各种蛋白质，包括'WhiB'蛋白质从结核病引起的细菌结核分枝杆菌。 我们将开发一种新技术。61镍同步穆斯堡尔光谱，这应该有广泛的应用，镍酶和化学一般。

 DESCRIPTION (provided by applicant): Biological Fe-S clusters are nanoparticles containing 2-8 Fe atoms that are held together primarily by bridging S atoms. Proteins that contain Fe-S clusters serve a wide variety of essential tasks in living systems, including catalysis of chemical reactions, sensing the chemical environment, signaling to and repair of DNA, and the maintenance of molecular structure. Our main goals for this proposal center on four key questions: How do Fe-S clusters react with small molecules? How do they catalyze reactions, how do they work as nitric oxide and oxygen sensors, and what happens when they decompose? What are the steps in assembly of the hydrogenase active site `H-cluster'? How does the larger protein environment affect access of small molecules to Fe-S sites? How does chemistry at an Fe-S cluster affect tertiary protein structure and interactions with DNA? The expected outcomes from our research include: Information about the catalytic intermediates of enzymes that fix nitrogen (nitrogenase) or produce hydrogen (hydrogenase) Information about reaction intermediates when Fe-S cluster proteins react with signaling molecules NO and O2, and changes that occur as the cluster sensor transduces the signal to affect DNA Information about side chain contributions and gas channels in gas-processing enzymes that process or are inhibited by small molecules such as N2, O2, CO, and NO. The approach to gain this information is spectroscopy. Using photolysis/FT-IR, NRVS, and resonance Raman spectroscopy, this work will characterize how nitrogenase (N2ase) binds the inhibitor CO, as well as the structures of its complex with N2 and more reduced intermediates, elucidate when and how hydrides bound at the active sites of the hydrogenases (H2ases), Using time-resolved spectroscopies on a variety of time-scales, we aim to define intermediates and final products for reactions of NO and O2 with [4Fe-4S] clusters in various proteins, including the `WhiB' proteins from the tuberculosis-causing bacterium Mycobacterium tuberculosis. We will develop a new technique. 61Ni synchrotron Mössbauer spectroscopy, that should have broad applications to Ni enzymes and to chemistry in general.