O2 ACTIVATION BY MOSSBAUER SPECTROSCOPY

这项建议旨在阐明铁的结构和功能- 含有与氧气活化有关的蛋白质。实验性的 所使用的技术是~(57)Fe穆斯堡尔谱和电子 顺磁共振。 (1)铁氧蛋白甲烷单加氧酶Delta9的研究 去饱和酶、甲苯-4-单加氧酶、核苷酸还原酶和烷烃 羟基酶将继续，并特别强调表征 FeII-FeII态的电子结构。此外，反应 中间体将被捕获和研究。 (2)这项研究将得到单核和核子研究的补充 双核络合物。 (3)拟议研究的许多方面涉及FeIV渗出 在酶反应循环的中间产物或AS中的状态 合成化合物反应中的瞬变现象。这项提案提出了一项 系统地研究蛋白质中FeIV的光谱以及 在特别准备的合成复合体中。 (4)对异青霉素N合成酶的研究将继续进行，特别是 重点是捕获假定的FeIV中间体。 (5)含Fe4S4簇的胞质乌头酸酶表现出酶活性 活动。作为一种脱脂蛋白，它的功能是铁反应结合。 转铁蛋白受体和转铁蛋白生物合成中的蛋白质。那里 是分析证据表明除了铁之外还存在额外的铁 那些包含在Fe4S4簇中的化合物。将尝试识别和识别 用穆斯堡尔谱表征额外的铁。 (6)对共价性质的实验和理论研究 亚硫酸盐大肠埃希氏菌亚铁血红素和Fe4S4簇之间的联系 还原酶将通过研究适当连接的合成物来执行 装配。 (7)模型络合物中反对称交换性质的研究 对于氰化物抑制的细胞色素氧化酶，将继续进行。 (8)最后，对电子产品的性质进行理论研究 FeIII-FeIV混合价二聚体的结构将继续， 重点探索双交换在化合物中的作用 低自旋位置。

This proposal seeks to elucidates the structure and function of iron- containing proteins involved in oxygen activation. The experimental techniques employed are 57Fe Mossbauer spectroscopy and electron paramagnetic resonance. (1) Studies of the iron-oxo proteins methane monooxygenase, delta9 desaturase, toluene-4-monooxygenase, ribonucleotide reductase, and alkane hydroxylase will be continued with particular emphasis on characterization of the electronic structures of the FeII-FeII states. Moreover, reaction intermediates will be trapped and studied. (2) This research will be complemented by studies of mononuclear and dinuclear complexes. (3) Many aspects of the proposed research involve the FeIV exudation state, either in intermediates of enzymatic reaction cycles or as transients in reactions of synthetic compounds. This proposal presents a systematic effort to study the spectroscopy of FeIV in proteins as well as in specially prepared synthetic complexes. (4) Studies of isopenicillin N synthase will be continued with special emphasis on trapping putative FeIV intermediates. (5) Cytosolic aconitase containing an Fe4S4 cluster exhibits enzymatic activity. As an apo-protein, it functions as the iron-responsive binding protein in the biosynthesis of transferrin receptor and transferrin. There is analytical evidence for the presence of an extra iron in addition to those contained in the Fe4S4 cluster. It will be attempted to identify and characterize the extra iron by Mossbauer spectroscopy. (6) Experimental and theoretical studies into the nature of the covalent link between the siroheme and the Fe4S4 cluster of E. coli sulfite reductase will be performed by investigating suitably linked synthetic assemblies. (7) Studies into the nature of antisymmetric exchange in model complexes for cyanide-inhibited cytochrome oxidase will be continued. (8) Finally, theoretical studies into the nature of the electronic structure of FeIII-FeIV mixed-valence dimers will be continued, with emphasis on exploring the role of double-exchange in compounds involving low-spin sites.