ELECTRONIC STRUCTURE OF IRON ENZYME INTERMEDIATES FROM HIGH-RESOLUTION RIXS

高分辨率 RIX 中铁酶中间体的电子结构

• 批准号: 8170326
• 负责人: EDWARD I SOLOMON
• 金额: $ 0.34万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170326
• 关键词: Chemistry; Computer Retrieval of Information on Scientific Projects Database; Energy Transfer; Enzymes; Funding; Goals; Grant; Heme; Hydrogen Bonding; In Situ; Institution; Iron; Life; Ligands; Metals; Methane hydroxylase; Methods; Modeling; Monitor; Photons; Process; Research; Research Personnel; Resolution; Resources; Shapes; Source; Spectrum Analysis; Theoretical model; Time; United States National Institutes of Health; Vacuum; electronic structure; multiplet; research study; tool; Chemistry; Computer Retrieval of Information on Scientific Projects Database; Energy Transfer; Enzymes; Funding; Goals; Grant; Heme; Hydrogen Bonding; In Situ; Institution; Iron; Life; Ligands; Metals; Methane hydroxylase; Methods; Modeling; Monitor; Photons; Process; Research; Research Personnel; Resolution; Resources; Shapes; Source; Spectrum Analysis; Theoretical model; Time; United States National Institutes of Health; Vacuum; electronic structure; multiplet; research study; tool

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of the proposed research is to develop 1s2p resonant inelastic x-ray scattering (RIXS) as a general and quantitative tool for studying enzyme intermediates. We have previously used metal L-edge spectroscopy at SSRL to extend the concept of metal-ligand covalency by showing that the L-edge band shape can be used to quantify interactions between ligands and metal d-orbitals of different symmetry, i.e., differential orbital covalency (DOC). The DOC method allows for experimental determination of basic concepts in chemistry. However, metal L-edge spectroscopy is performed with soft x-rays in ultra-high vacuum and cannot in general be used for enzyme intermediates. 1s2p RIXS involves excitation from 1s 3d (h ~ 7.1 keV) and monitoring of the subsequent 2p 1s photon emission (h2 ~ 6.4 keV). The final state in this resonance process is 2p53dn+1, the same final state as for the L-edge experiment. 1s2p RIXS uses hard x-rays and does not require ultra-high vacuum, and can therefore be used to obtain L-edge-like spectra under in situ conditions. Our new contribution is a quantitative analysis of RIXS spectra in the energy transfer (h - h2) direction using the DOC analysis. The long life time of the 2p hole results in a sharp and feature-rich spectrum that can be accurately fitted using a parameterized multiplet model that includes configuration interaction. The electronic structure, including the DOC, is subsequently extracted from the theoretical model. The method will be used to study high-valent enzyme intermediates that activate inert C?H bonds; heme compounds I and II, the non-heme ferrryl-oxo intermediate in SyrB2 and intermediate Q in the binuclear iron enzyme methane monooxygenase. RIXS provides a new tool to investigate the requirements for C?H bond activation, but also to explain differences in reactivity between heme and non-heme enzymes.

该副本是利用众多研究子项目之一 由NIH/NCRR资助的中心赠款提供的资源。子弹和 调查员（PI）可能已经从其他NIH来源获得了主要资金， 因此可以在其他清晰的条目中代表。列出的机构是 对于中心，这不一定是调查员的机构。 拟议的研究的目的是开发1S2P共振非弹性X射线散射（RIX）作为研究酶中间体的一般和定量工具。我们以前在SSRL处使用了金属L边缘光谱法来扩展金属 - 配体共价概念，以表明L-EDGE带状形状可用于量化不同对称性的配体与金属D-轨道之间的相互作用，即差异轨道的差异轨道协调（DOC）。 DOC方法允许实验化学中的基本概念。但是，在超高真空中使用软X射线进行金属L边缘光谱法，通常不能用于酶中间体。 1S2P RIX涉及从1S 3D（H〜7.1 KEV）的激发，并监测随后的2P 1S光子发射（H2〜6.4 KEV）。此共振过程中的最终状态为2p53dn+1，最终状态与L边实验相同。 1S2P RIX使用硬X射线，不需要超高的真空，因此可以在原位条件下使用L-EDGE样光谱。我们的新贡献是使用DOC分析对能量传输（H -H2）方向的RIX光谱进行定量分析。 2P孔的长寿命会产生鲜明且功能丰富的频谱，可以使用包括配置相互作用的参数化多重组模型准确地拟合。随后从理论模型中提取了包括DOC在内的电子结构。该方法将用于研究激活惰性C键的高价值酶中间体。血红素化合物I和II，Syrb2中的非血红素铁氧化物中间体和双核铁酶甲烷单加氧酶中的中间Q。 RIX提供了一种新工具来研究C键激活的要求，还可以解释血红素和非血红素酶之间反应性的差异。