CU XAS STUDIES OF MULTICOPPER OXIDASES

多铜氧化酶的 CU XAS 研究

• 批准号: 6586691
• 负责人: EDWARD I SOLOMON
• 金额: $ 14.32万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6586691
• 关键词: biomaterials; biomedical resource; proteins; spectrometry; structural biology

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.

提议对存在于的三核位点进行 XAS 研究 多铜氧化酶。 完全还原、完全氧化和氧气 天然漆酶和 1 型汞取代漆酶的中间形式 (Lc) 将由 EXAFS 进行调查，以探测可能的金属-金属 表明三核处存在氧桥的相互作用 位点并确定是否存在短的 Cu-O 相互作用 第一个关于中间体的 shell 数据。 我们将量化数量 Cu(I) 存在于两种使用 Cu K 边缘结构的中间体中。 T1Hg Lc、天然 Lc 和抗坏血酸的过氧化物和叠氮化物结合形式 氧化酶（AO）也将通过EXAFS和X射线进行系统研究 吸收边方法将光谱结果与 AO 配体结合形式的晶体学数据。 这些实验 对于加深对角色的理解至关重要 双氧四电子还原中的三核位点 水。 最后，XAS 研究将针对铜蓝蛋白 (Cp) 探测异常情况下铜的氧化态（即 EPR 不可检测的）似乎存在的三核铜簇 以该酶的静止形式快速制备并 阐明三核铜之间可能的相互作用 与其他多铜氧化酶相比。