STAFF PRIORITY TIME FE K & CU K XAS STUDIES OF CYTOCHROME OXIDASE & MODELS

员工优先时间 FE K

• 批准号: 6658728
• 负责人: BRITT HEDMAN
• 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/6658728
• 关键词: biological products; biomaterials; biomedical resource; proteins; spectrometry; structural biology; technology /technique

Cytochrome oxidase (CcO) is known to possess four metal centers - two heme and two Cu sites. The catalytic center of CcO is defined by the two metal sites, heme a3 and CuB, which are associated to form a binuclear center. Numerous studies have propose that the two metal centers be closely spaced and bridged, but the identity of the bridging ligand in the "as-isolated" enzyme remains unresolved. Work at Harvard has given rise to several binuclear synthetic complexes which are viable analogs of the CcO site. They include a bridged Fe(III)-O-Cu(II) complex which reproduces the most prominent electronic features of the oxidized CcO site, and a CN- bridged analog which has potential relevance to cyanide toxicity. These analogues present a significant challenge for EXAFS analysis because: i) from the Fe viewpoint the octaethylporphrin ligand is rigid and contributes significant multiple scattering (MS) terms to the overall EXAFS signal, ii) a mono bridge, such as O2- will contribute strong MS as the bridge angle approaches linearity and be a significant contributor from either the Cu or the Fe EXAFS viewpoint, and iii) multinuclear bridges, such as CN- could have very complicated 4-body MS interactions (again angularly dependent). We intend to perform complete MS XAS analysis on these models and enzymes.

已知细胞色素氧化酶（CCO）拥有四个金属中心 - 两个血红素和两个Cu位点。 CCO的催化中心由 两个金属位点，血红素A3和Cub，与形成A相关 双核中心。 许多研究提出了两种金属 中心的间隔和桥接紧密，但是 “隔离”酶中的桥接配体仍未解决。 工作 哈佛大学已引起了几种双核合成复合物 这是CCO站点的可行类似物。 他们包括一个桥接的 Fe（iii）-o-cu（ii）复合物，重现了最突出的 氧化CCO位点的电子特征和一个桥接的类似物 与氰化物毒性具有潜在相关性。 这些类似物 对EXAFS分析提出了重大挑战，因为：i）来自 Fe观点八甲基孢子蛋白配体是刚性的，有助于 总体EXAF的大量散射（MS）术语 信号，ii）单桥（例如O2-）将贡献强大的MS 桥角接近线性并成为重要的贡献者 从Cu或Fe Exafs的角度来看，iii）多核 桥梁（例如CN-）可能具有非常复杂的4体MS 相互作用（再次有角度依赖）。 我们打算执行 对这些模型和酶进行完整的XAS分析。