HEMEPROTEINS STATIC & RAPID KINETIC MAGNETIC STUDIES

静态血红素蛋白

• 批准号: 3337788
• 负责人: John Philo
• 金额: $ 7.25万
• 依托单位: UNIVERSITY OF CONNECTICUT STORRS
• 依托单位国家: 美国
• 财政年份: 1979
• 资助国家: 美国
• 起止时间: 1979-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3337788
• 关键词: blood proteins; chemical binding; conformation; cytochromes; electron spin resonance spectroscopy; ferredoxin; heme; hemoglobin As; hemoglobin Ss; hydrogenase; ligands; metalloproteins; methemoglobin; oxygen tension; oxyhemoglobin; phosphates; thermodynamics

The techniques of magnetic susceptibility and rapid reaction kinetics will be used to study the thermodynamic and kinetic linkages between changes in protein conformation and iron electronic configuration in hemoglobin A, other mutant hemoglobins, and various metalloproteins. To accomplish this we have developed a unique high-sensitivity time-resolved magnetic susceptometer. This instrument, which is based on recent advances in superconducting technology, is nearly 100 times more sensitive that conventional susceptometers, and provides microsecond time resolution to make possible the study of the rapid kinetics of spin state changes in hemoglobins and other metalloproteins. This new Time-Resolved Magnetic Susceptibility (TREMS) method also can be used to investigate the influence of subunit association on spin state dynamics in dimeric and tetrameric hemeproteins or in extended assemblies such as hemoglobin S. While the mechanism of cooperative oxygen binding to hemoglobin is still not known, current proposals invoke coupling of spin state changes to conformational changes. We propose some critical tests of the Perutz stereochemical model of cooperativity, and measurements to quantitate the linkage between quaternary structure and spin state. These magnetic studies will be carried out in parallel with both equilibrium and kinetic optical spectroscopic measurements of the same allosterically modifiable hemoglobins. A number of other metalloproteins will be studied to answer specific questions of electronic configuration and structure. For example, measuring the antiferromagnetic coupling in the invertebrate oxygen carriers hemocyanin and hemerythrin will elucidate the mode by which a single O2 is bound to two metal ions. The magnetic properties of other hemeproteins and iron-sulfur proteins will also be explored.

磁化率和快速反应动力学的技术将 用于研究变化之间的热力学和动力学联系 血红蛋白A中的蛋白质构象和铁电子构型 其他突变血红蛋白和各种金属蛋白。 实现这一目标 我们已经开发了独特的高敏性时间分辨磁 启示仪。 该工具是基于最新进展的 超导技术的敏感性几乎是100倍 常规的苏伯特计，并提供微秒的时间分辨率 使可能研究旋转状态变化的快速动力学 血红蛋白和其他金属蛋白。 这个新的时间分辨磁 易感性（TREM）方法也可用于研究影响 二聚体和四聚体中自旋状态动力学的亚基关联 血蛋白或在延长的组装中，例如血红蛋白S。 合作氧与血红蛋白结合的机制尚不清楚， 当前的建议调用旋转状态变化以构象的耦合 更改。 我们提出了佩鲁茨立体化学模型的一些关键测试 合作性和测量值 第四纪结构和旋转状态。 这些磁性研究将是 与平衡和动力学光学同时进行 相同变构修改的光谱测量 血红蛋白。 将研究许多其他金属蛋白以回答 电子配置和结构的具体问题。 例如， 测量无脊椎动物氧中的抗铁磁耦合 携带者血氰酸蛋白酶和hemerythrin将阐明一种模式 单个O2与两个金属离子结合。 其他的磁性 还将探索消息蛋白和铁硫蛋白。