Iron-sulfur cluster electronic structural evolution and its contribution to diverse functionality

该提案建立在申请人在SPP 1927的第一个资助期内获得的结果的基础上，这些结果已经导致我们自己的团体以及与其他SPP成员合作的五个出版物。该项目的重点是了解自然界和模型系统中复杂铁硫簇合物的详细电子结构。最终目标是深入了解这些系统的独特反应性，特别强调固氮酶和氢化酶。第一个资助期包括一个光谱学和一个面向理论的分支研究。在光谱取向部分，2 p3 d共振非弹性X射线散射（RIXS）和X射线磁性圆二色性（XMCD）已被开发为Fe/S位点的局部电子结构的独特探针。理论研究的目的是在详细的基于第一原理波函数的计算的基础上开发新的模型哈密顿量，这将允许计算寡聚物簇的光谱观测值，这太复杂了，无法通过量子化学进行严格处理。在本建议中，这两个分支的研究将进一步扩展，并有望最终收敛到独特的结合实验和理论协议的Fe/S网站的电子结构的说明。为此，我们的2 p3 d RIXS研究将专注于获得更高分辨率的数据，以进一步增强定量信息。此外，我们将进一步探索XMCD作为一种互补的，强大的技术研究的Fe/S网站，并将其应用到固氮酶的活性位点，以及氢化酶。在实验的发展，我们将继续我们的研究从头推导模型哈密顿。目前，这些研究涵盖单体和二聚体Fe/S网站的细节。第二个资助期的主要目标是开发必要的框架，以处理从三聚体和四聚体到固氮酶的FeMoco活性位点（生物学中最复杂的活性位点）的更高核性。我们还将把重点放在发展必要的框架，从模型的哈密顿处理计算磁性和X射线光谱特性。最终，我们希望利用开发的协议，以获得基本的洞察自然界的进化生物合成途径的FeS集群组装的电子结构的后果。除了探索这些新的研究领域，我们将继续并加强我们在SPP与弗兰克迈耶，奥利弗Einsle和马蒂亚斯博尔等团体的合作努力。

This proposal builds upon the results that the applicants have obtained in the first funding period of the SPP 1927 and that have already led to five publications from our own groups and in collaboration with other SPP members. The project is centered around understanding the detailed electronic structure of complex iron-sulfur clusters in nature and in model systems. The ultimate goal is to develop insight into the unique reactivity of these systems, with special emphasis on nitrogenase and hydrogenase. The first funding period contained a spectroscopy- and a theory-oriented branch of research. In the spectroscopy-oriented part, 2p3d resonant inelastic x-ray scattering (RIXS) and X-ray magnetic circular dichroism (XMCD) have been developed as unique probes of the local electronic structure of Fe/S sites. The theoretical research was directed towards developing new model Hamiltonians on the basis of detailed first-principle wavefunction based calculations that will allow the calculation of spectroscopic observables for oligonuclear clusters, which are too complex to be rigorously treated by quantum chemistry. In the present proposal, both branches of research will be further extended and are expected to eventually converge into unique combined experimental and theoretical protocol for the elucidation of Fe/S site electronic structure. To this end, our 2p3d RIXS studies will focus on obtaining higher resolution data to further enhance the quantitative information. In addition, we will further explore XMCD as a complementary, powerful technique for the study of Fe/S sites and will apply it to the active sites of nitrogenase, as well hydrogenase. In parallel with the experimental developments, we will continue our studies on ab initio derived model Hamiltonians. Presently, these studies cover monomeric and dimeric Fe/S sites in detail. The major goal of the second funding period is to develop the necessary framework to treat higher nuclearities from trimers and tetramers, all the way to the FeMoco active sites of nitrogenase, the most complex active site in biology. We will also put major emphasis on developing the necessary framework to calculate magnetic and X-ray spectroscopic properties from the model Hamiltonian treatment. Eventually, we hope to utilize the developed protocols to obtain fundamental insights into the electronic structural consequences of nature’s evolved biosynthetic pathways in FeS cluster assembly. In addition to exploring these new research areas, we will continue and intensify our collaborative efforts in the SPP with the groups of Franc Meyer, Oliver Einsle and Matthias Boll, among others.