Heme/Copper and Heme/Nonheme Iron O(2) and NO Reactivity

项目摘要(最多30行) 长期的研究目标是设计、合成和研究模型化合物系统 可以帮助阐明结构、金属连接、光谱学和反应性的基本方面 由血红素-铜氧化酶(HCOS)和一氧化氮还原酶(NORs)利用的化学。这些 进化上相关的酶在好氧和厌氧生物的生物能量学中起着关键作用， 并具有共同的血红素/M(M=铜或非血红素铁)活性中心，该活性中心可还原裂解 分别为氧气(O2)或一氧化氮(NO)。建议的研究可以有助于 更好地理解酶的结构和机制，并提供对 氧气和一氧化氮的生物处理，氮氧化物的化学和生物化学，以及 解决与环境中的氮氧化物有关的问题。具体目标包括(1)人物塑造 新的质子化和新的低自旋衍生物--血红素-过氧铜配合物的合成及其过氧化性质的研究 连接性和电子结构，(2)已经很好地促进了还原O-O裂解的研究 表征了血红素-过氧-铜络合体系，并阐明了这一过程的关键因素， 在化学或生物化学系统中包含‘氧气活化’的一个关键方面，(3)新的设计 具有连接的苯酚-咪唑部分的铜的配体，以阐明这种基团可能会如何 O-O裂解化学的一部分，即HCO功能。其他新的血红素/铜双核配体将是 旨在测试酶在自然界中如何形成His-Tyr交联物，(4)对血红素/NO/O2的研究 配位化学--包括明显可逆形成的二亚硝基血红素络合物和 模拟血红素蛋白在非加氧酶中的作用，(5)研究的新方法 研究了亚铁血红素/非亚铁血红素和亚铁血红素/铜络合物的NO还原酶活性，包括设计了多个 系统考察双金属化学体系还原偶联两个NO的能力 产生一氧化二氮(N2O)的分子，以及(6)详细研究了 血红素、亚铁血红素/铜和亚铁血红素/非亚铁络合物中的一氧化氮光引发 反应可以提供对动力学、热力学和金属的详细了解。 这些小分子在与血红素/非血红素金属位置相互作用中的偏好/迁移，这是相关的 与HCO和NOR生物化学有关。

Project Summary (30 lines maximum) The long-term research objective is to design, synthesize and investigate model compound systems which can help elucidate fundamental aspects of structure, metal ligation, spectroscopy and reactivity relevant to the chemistry utilized by heme-copper oxidases (HCOs) and nitric oxide reductases (NORs). These evolutionarily related enzymes play critical roles in the bioenergetics of aerobic and anaerobic organisms, and have in common a heme/M (M = copper or non-heme iron) active site which reductively cleaves dioxygen (O2) or nitric oxide (NO, nitrogen monoxide), respectively. The research proposed can contribute to a better understanding of enzyme structure and mechanism and provide fundamental insights into the biological processing of dioxygen and NO, the chemistry and biochemistry of nitrogen oxides, as well as address issues related to nitrogen oxides in the environment. Specific aims include (1) the characterization of heme-peroxo-Cu complexes, new protonated and new low-spin derivatives and elucidation of their peroxo- connectivity and electronic structures, (2) the study of reductive O-O cleavage promoted by already well characterized heme-peroxo-Cu complex systems, and elucidation of the factors crucial for this process, comprising a critical aspect of 'oxygen activation' in chemical or biochemical systems, (3) the design of new ligands for copper which possess a linked phenol-imidazole moiety, to elucidate how such a group may take part in O-O cleavage chemistry, i.e., HCO function. Other new binucleating ligands for heme/Cu will be designed to test how in nature the enzyme His-Tyr crosslink might form, (4) investigation of heme/NO/O2 coordination chemistry - including the apparent reversible formation of a dinitrosyl heme complex and modeling heme protein actions such as occur in enzyme NO-dioxygenases, (5) new approaches to the study of NO reductase activity of heme/non-heme diiron and heme/Cu complexes, including design of a number of dimetal chemical systems for the systematic interrogation of their ability to reductively couple two NO molecules to produce nitrous oxide (N2O), and (6) detailed investigations of the metal-binding dynamics of nitrogen monoxide in heme, heme/copper and heme/non-heme diiron complexes - such photoinitiated reactions can provide a detailed understanding of the kinetics, thermodynamics, and metal preference/migration of these small molecules in interactions with heme/non-heme metal sites, as is relevant to HCO and NOR biological chemistry.