HALIDE XAS STUDIES OF PHOTOSYNTHETIC WATER OXIDATION COMPLEX

光合水氧化复合物的卤化物XAS研究

• 批准号: 6586692
• 负责人: MELVIN P KLEIN
• 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/6586692
• 关键词: biomaterials; biomedical resource; plants; proteins; spectrometry; structural biology

Photosynthetic water oxidation is catalyzed by a cluster of 4 Mn atoms. Chloride and calcium are essential cofactors for oxygen evolution activity. It has been postulated that halide is a ligand to Mn, but the evidence at present is not conclusive. Cl K-edge studies by Hedman et al (Hedman, B., Hodgson, K.O. & Solomon, E.I. (1990) J. Am. Chem. Soc. 112, 1643-1645) have shown that there is a distinctive pre-edge feature in the K-edge spectrum of Cl when it is a ligand to transition metals. The feature was assigned to a Cl 1s to metal 3d transition, which becomes allowed due to mixing with empty d-orbitals. Such a pre-edge feature is present only when Cl- is ligated to a metal with empty d-orbitals. We propose to collect Cl K-edge spectra of photosystem II samples containing only the minimal amount of Cl-required (1Cl/4Mn) for activity to determine whether Cl is ligated to Mn.

光合水氧化是由4 mn的簇催化的 原子。 氯化物和钙是氧气的必需辅助因子 进化活动。 有人认为卤化物是 MN，但目前的证据不是结论性的。 Cl K边缘研究 Hedman等人（Hedman，B.，Hodgson，K.O。＆Solomon，E.I。（1990）J。 是。化学 Soc。 112，1643-1645）表明有一个独特的 当它是配体的k边缘频谱中的前边缘特征 过渡金属。 该功能被分配给CL 1S到金属3D 过渡，由于与空的D轨道混合而允许。 仅当Cl-连接到金属时才存在这样的预埃格特征 带有空的D轨道。 我们建议收集Cl K-Edge的光谱 光系统II样品仅包含最小的 Cl-Cl-nequired（1CL/4MN）的活性以确定CL是否被连接 到Mn。