XAS STUDIES OF CPD I INTERMEDIATES

XAS研究建议对存在于三核中心的 多铜氧化物酶。完全还原、完全氧化和氧气 天然和1型汞取代漆酶的中间体 (LC)将接受EXAFS的调查，以探测可能的金属-金属 表明氧桥接在三核的相互作用 站点并确定是否存在短暂的铜-氧相互作用 首先是关于中间体的壳数据。我们将量化 两种中间体中的铜(I)均以铜K边结构存在。 T1HgLC、天然LC和抗坏血酸的过氧化氢和叠氮结合形式 还将用EXAFS和X-射线系统地研究氧化物酶(AO) 用吸收边方法将光谱结果与 关于配体结合形式的AO的结晶学数据。这些实验 对于发展对这一角色的理解至关重要 二氧四电子还原中三核中心的位置 水。最后，XAS研究将定向到铜蓝蛋白(CP)以 探查异常(即EPR)中铜的氧化状态 不可检测)似乎存在的三核铜团簇 在快速制剂中以这种酶的休眠形式和 阐明三核铜之间可能的相互作用如下 与其他多铜氧化物酶相比。

XAS studies are proposed for the trinuclear sites present in the multicopper oxidases. The fully reduced, fully oxidized and oxygen intermediate forms of native and type 1 mercury substituted laccase (Lc) will be investigated by EXAFS to probe for possible metal-metal interactions which would indicate oxygen bridging at the trinuclear site and to determine if a short Cu-O interaction is present in the first shell data on the intermediates. We will quantify the amount of Cu(I) present in both intermediates using the Cu K-edge structure. Peroxide and azide bound forms of T1Hg Lc, native Lc, and ascorbate oxidase (AO) will also be systematically studied by EXAFS and X-ray absorption edge methods to correlate spectroscopic results with crystallographic data on ligand bound forms of AO. These experiments are of critical importance in developing an understanding of the role of the trinuclear site in the four electron reduction of dioxygen to water. Finally XAS studies will be directed to ceruloplasmin (Cp) to probe the oxidation state of the coppers in the unusual (i.e. EPR nondetectable) trinuclear copper cluster which appears to be present in the resting form of this enzyme in rapid preparations and to elucidate the possible interactions among the trinuclear coppers as compared with other multicopper oxidases.