XES AND XAS STUDIES OF SOLUBLE METHANE MONOOXYGENASE

可溶性甲烷单加氧酶的 XES 和 XAS 研究

• 批准号: 8362359
• 负责人: SERENA D DE BEER GEORGE
• 金额: $ 1.45万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8362359
• 关键词: Active Sites; Bacteria; Binding; Biological Process; Complement; Complex; Data; Diamond; Dioxygen; Funding; Grant; Hydroxylation; Measures; Methane; Methane hydroxylase; Methods; Modeling; National Center for Research Resources; Nature; Oxygen; Principal Investigator; Radiation; Research; Research Infrastructure; Resources; Source; Structure; Theoretical Studies; United States National Institutes of Health; computer studies; cost; electronic structure; emission spectroscopy; insight; research study; structural biology

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Biologically, the hydroxylation of methane is carried out by methane monoxygenases(MMO) found in methantrophic bacteria. The soluble form of MMO utilizes a diiron active site, which reacts with dioxygen to generate a -peroxo-Fe(III)Fe(III) species (MMO-P) and then an Fe(IV)Fe(IV) species (MMO-Q), which is responsible for oxidizing methane. The intermediates of the MMO catalytic cycle have been the subject of intense experimental and theoretical studies. However, MMO-Q and MMO-P have eluded structural characterization, and many questions about the nature of these intermediates remain. The experimental data for MMO-P have been used to argue for a cis-mu-1,2-peroxo bridging mode, while computational studies favor a mu-2:2-O2 core. For MMO-Q the 2.5 ¿ Fe-Fe distance from EXAFS favors a bis-mu-oxo Fe(IV)-Fe(IV) diamond core structure. However, no vibrational data exist to support any of the postulated core structures and the mechanism for conversion of MMO-P to MMO-Q is unknown. The proposed research is aimed at elucidating the electronic structure of these key intermediates in methane hydroxylation by utilizing new spectroscopic methods. K-Beta x-ray emission spectroscopy is proposed as a selective probe of the Fe2O2 upper valence region, which should provide a sensitive measure of the oxygen bond strength and the binding mode. These data will be complemented by conventional XAS data and correlated to DFT calculations of the spectra. Our initial studies will focus on well characterized model complexes and will then be extended to the enzymatic intermediates. The results of these studies should provide fundamental insights into the biological process of methane hydroxylation.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 从生物学上讲，甲烷的羟基化是通过在甲烷一氧酶（MMO）中发现的甲烷一氧酶（MMO）进行的。 MMO的可溶性形式利用了一个Diron活性位点，该位点与二氧化物反应产生-FE（III）Fe（III）种类（MMO-P），然后是Fe（IV）Fe（IV）Fe（IV）物种（MMO-Q），该物种（MMO-Q）负责氧化甲烷。 MMO催化循环的中间体已成为激烈的实验和理论研究的主题。但是，MMO-Q和MMO-P具有结构性的表征，并且有关这些中间体的性质的许多问题仍然存在。 MMO-P的实验数据已用于为CIS-MU-1,2-Peroxo桥接模式争辩，而计算研究有利于MU-2：2-O2核心。对于MMO-Q，距Exafs的2.5»Fe-Fe距离更喜欢Bis-Mu-oxo Fe（IV）-Fe（IV）钻石核心结构。但是，尚无振动数据来支持任何已发布的核心结构，MMO-P转换为MMO-Q的机制尚不清楚。拟议的研究旨在通过利用新的光谱法阐明这些关键中间体在甲烷羟基化中的电子结构。 K-Beta X射线发射光谱是作为Fe2O2上价区域的选择性探针的，该探针应提供对氧键强度和结合模式的敏感度量。这些数据将通过常规XAS数据完成，并且与光谱的DFT计算有关。我们的最初研究将集中在表征良好的模型复合物上，然后将其扩展到酶促中间体。这些研究的结果应提供对甲烷羟基化生物学过程的基本见解。