RESONANCE SPECTROSCOPY OF METALLOPROTEINS

我们建议研究分子的电子结构和分子结构。 金属蛋白中的活性中心主要是利用磁性 共振和穆斯堡尔谱学。我们的主要兴趣集中在 与O_2-H_2O-H_2O_2氧化还原相互作用的铁蛋白 系统。其最终目标是阐明结构和动态 控制反应路径的功能。研究将会 沿着几条路线继续前进。(一)我们会对事件进行调查 导致细胞色素P450CAM中的氧激活， 特别强调了两国之间的复杂地层 单加氧酶和2Fe-2S rdox/效应蛋白， 恶臭毒素。两种方法的EPR/Endor参数比较 分离的蛋白质与双分子复合体的蛋白质应该 揭示自旋-自旋相互作用和/或构象的影响 改变。为了支持赋值，putidaredosin的同源性 利用已知的藻类铁氧还蛋白的结构，将通过 Endor在H2O/D2O中。(Ii)会尝试诱捕 电子，通过低温辐解，在血红素-O2络合物上 底物结合的OxP450CAM。将使用EPR和Endor 预期的血红素-O2自由基及其反应的探讨 对产品进行退火热处理。(Iii)跟进观察到的 脱氧肌球蛋白中的EPR信号(21)我们将探索其他S=2 在血红素和非血红素铁蛋白的状态下，这种信号。这个 能级和跃迁几率将由自旋建模 具有参数分布的哈密顿量。单晶和 高频电子顺磁共振以及穆斯堡尔谱学将是 用来进一步了解能级的分布 在这些系统中。(Iv)与本地化学家合作及 在其他大学，我们将继续我们的EPR和Mossbauser 过氧化物酶中高级氧化态中间体的研究 和过氧化氢酶，以及自旋耦合的双核簇合物 高氯氰菊酯和紫色酸性磷酸酶。模型系统将是 与金属蛋白进行分析比较，如果它们有希望的话 进一步的洞察。

We propose to study the electronic and molecular structure of active centers in metalloproteins using primarily magnetic resonance and Mossbauer spectroscopy. Our main interest focuses on iron proteins that interact with the O2-H2O-H2O2 redox system. The ultimate goal is to elucidate structural and dynamic features that control the reaction pathways. Research will proceed along several lines. (i) We will investigate the events leading to dioxygen activation in cytochrome P450CAM, with specific emphasis on complex formation between the monooxygenase and the 2Fe-2S rdox/effector protein, putidaredoxin. Comparisons of EPR/ENDOR parameters of the isolated proteins with those of the bimolecular complex should reveal effects of spin-spin interactions and/or conformational changes. To support assignments, the homology of putidaredoxin with the known structure of algal ferredoxin will be examined by ENDOR in H2O/D2O. (ii) Attempts will be made to trap an electron, by low temperature radiolysis, on the heme-O2 complex of substrate-bound oxyP450CAM. EPR and ENDOR will be used to probe for the expected heme-O2 radical and its reaction products on annealing. (iii) To follow up on the observation of an EPR signal in deoxymyoglobin (21) we will explore other S=2 states in heme and non-heme iron proteins for such signals. The energy levels and transition probabilities will be modeled by a spin Hamiltonian with a distribution of parameters. Single-crystal and high-frequency EPR, as well as Mossbauer spectroscopy, will be used to gain further insight into the distribution of energy levels in these systems. (iv) In collaboration with chemists locally and at other universities we will continue our EPR and Mossbauser studies of higher oxidation state intermediates in the peroxidases and catalases and of the spin-coupled binuclear clusters in hemerythrin and purple acid phosphatase. Model systems will be analyzed for comparison with metalloproteins if they promise further insights.