XAS ELECTRONIC AND GEOMETRIC STRUCTURAL STUDIES OF COPPER REDOX CENTERS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们建议扩展我们之前对质体青素的研究，使用S K-， Cu L-， Cu K-edge和EXAFS光谱的组合来定义含Cu电子转移蛋白的电子和几何结构。我们研究的第一部分将集中在理解经典蓝铜位点和扰动蓝铜位点之间的差异。一系列天然和突变蛋白，其中轴向配体是系统变化的，将提供对轴向配体和其他控制蓝铜位点氧化还原活性的因素的作用的见解。第二部分将重点研究细胞色素c氧化酶和氧化亚氮还原酶的CuA中心。我们感兴趣的是确定Cu A中基态波函数的性质，确定对位点离域的贡献，并深入了解配体场对金属-金属键形成的贡献。这将通过Cu K-， S K-和Cu l -边的各向同性研究，以及通过极化Cu K-和S K-边的研究来实现。

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. We propose to extend our previous studies on plastocyanin, using a combination of S K-, Cu L-, and Cu K-edge and EXAFS spectroscopies, to define the electronic and geometric structure of Cu-containing electron transfer proteins. The first part of our studies will focus on the understanding the differences between classic blue Cu sites and perturbed blue copper sites. A series of native and mutant proteins, where the axial ligand is systematically varied, will provide insight into the role of the axial ligand and other factors that control redox activity in blue copper sites. The second part of our studies will focus on the CuA center of cytochrome c oxidase and nitrous oxide reductase. We are interested in determining the nature of the ground state wave function in Cu A, defining contributions to the delocalization of the site, and gaining insight into ligand field contributions to metal-metal bond formation. This will be achieved through isotropic studies at the Cu K-, S K-, and Cu L-edge, as well as through polarized Cu K- and S K-edge studies.