XAS OF MOLYBDENUM ENZYMES

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。钼是唯一在生命系统中具有已知功能的第二行过渡元素。它在几乎所有生物的酶系统中发挥着功能作用，从细菌到植物到无脊椎动物和哺乳动物。钼酶都含有由一种不寻常的含硫辅助因子结合的金属。尽管具有共同的结构元素，这些酶在催化的不同化学反应的范围内是显着的，尽管几乎所有的是双电子氧化还原反应，其中氧原子被转移到钼上或从钼上转移。钼酶所扮演的功能角色同样多样；例如，它们在微生物呼吸、绿色植物吸收氮、控制昆虫眼睛颜色和人类健康方面发挥着重要作用。本文提出的工作是利用x射线吸收光谱对钼酶的主要家族进行系统的研究。将使用一种新的高分辨率方法，可以更详细地描述活性位点。这项工作的最终目标是对酶使用的催化机制进行深入的定量结构和电子理解，并在不同家族之间和内部对它们进行比较和对比。由此，我们希望提高我们对钼酶如何实现其显著功能多样性的理解。

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. Molybdenum is the only second-row transition element with a known function in living systems. It fulfills functional roles in enzyme systems in almost all living creatures, from bacteria through plants to invertebrates and mammals. The molybdenum enzymes all contain the metal bound by an unusual sulfur-containing cofactor. Despite possessing common structural elements, the enzymes are remarkable in the range of different chemical reactions that are catalyzed, although almost all are two-electron oxidation-reduction reactions in which an oxygen atom is transferred to or from the molybdenum. The functional roles filled by molybdenum enzymes are equally diverse; for example, they play essential roles in microbial respiration, in the uptake of nitrogen in green plants, in controlling insect eye color, and in human health. The proposed work is a systematic study of the major families of molybdenum enzymes using x-ray absorption spectroscopy. A new high-resolution approach will be used that allows the active sites to be described in much more detail. The ultimate goal of the work is to develop an in-depth quantitative structural and electronic understanding of the catalytic mechanisms used by the enzymes, and to compare and contrast them between and within the different families. From this we hope to improve our understanding of how molybdenum enzymes achieve their remarkable functional diversity.