IRON K-EDGE XAS STUDIES OF NON-HEME IRON ENZYMES, INTERMEDIATES, AND MODEL SYSTE

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 在蛋白质的研究中，特别是对于反应中间体，有几种情况下，共振拉曼、EPR、UV-VIS和MCD等光谱方法无法提供活性中心的电子结构和几何结构的完整图像。在这种情况下，就像许多非血红素铁酶的情况一样，使用Fe-K XAS EDGE和EXAFS技术可以提供关键的信息。Fe K边分析可以解决模糊的氧化态和精炼金属配位，EXAFS分析可以澄清配体排列、键长和整体配位范围。为了了解配位环境如何影响酶活性中心的电子结构以及机理转换，我们特别建议将XAS与我们的其他光谱技术相结合，以了解几种非血红素铁酶、模型体系和反应中间体的活性中心。特别感兴趣的体系包括：酪氨酸羟基酶、卤代酶、Rieske双加氧酶、吲哚双加氧酶、几个{FeNO}7类似物、FeIV=O体系的模型络合物，以及核苷酸还原酶中活性部位的双核铁多肽体系。

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. In the study of proteins, in particular for reaction intermediates, there are several cases in which spectroscopic methods such as resonance Raman, EPR, UV-vis, and MCD are unable provide a complete picture of the electronic and geometric structure of the active site. In such situations, as is the case for many non-heme iron enzymes, the use of Fe-K XAS edge and EXAFS techniques can provide crucial information. Fe K-edge analysis can resolve ambiguous oxidation states and refine metal coordination, and EXAFS can clarify ligand arrangement, bond length, and the overall coordination sphere. In order to understand how coordination environment affects electronic structure of enzymatic active sites as well as mechanistic turnover, we propose specifically to integrate XAS with our other spectroscopic techniques in order to understand the active sites of several non-heme iron enzymes, model systems, and reaction intermediates. Systems of specific interest include: tyrosine hydroxylase, halogenases, Rieske dioxygenases, intradiol dioxygenases, several {FeNO}7 analogs, model complexes of FeIV=O systems, and the binuclear iron systems of ¿due ferri¿ polypeptides for the active site in ribonucleotide reductases.