METHANE MONOOXYGENASE STRUCTURE/FUNCTION

描述：PI建议研究3D结构、活性部位 结构、催化机理和活化机理 来自II型甲烷营养菌Methylosinus的甲烷单氧酶 毛孢菌OB 3b. 这种酶催化氧化的第一步， 甲烷转化为CO2。 通过这种方式， 几乎所有的大量生物甲烷的出口（一个强大的 温室气体）。 MMO也 偶然催化许多其它烃的氧化， 在合成和生物降解中的应用。 迄今为止的工作表明， 该反应由在其它加氧酶中未发现的辅因子催化， 这意味着氧气活化的新策略。 拟议的研究建立 在过去的资助中取得的重大进展， 期间，并侧重于：物理和电子结构的阐明 双核铁簇合物的活性中心以及机理 由该中心催化的氧活化;光谱和动力学 表征了几种反应中间体， 在催化序列中鉴定;蛋白质-蛋白质的阐明 调节其活性的酶的三种多肽之间的相互作用 催化活性

DESCRIPTION: The PI proposes to investigate the 3D structure, active site architecture, catalytic mechanism and mechanism of activation of soluble methane monooxygenase from the Type II methanotroph Methylosinus trichosporum OB3b. This enzyme catalyzes the first step in the oxidation of methane to CO2 by methanogenic bacteria. In this way, the atmospheric egress of nearly all the enormous quantity of biogenic methane (a potent greenhouse gas) generated by anaerobic bacteria is prevented. MMO also adventitiously catalyzes the oxidation of many other hydrocarbons leading to applications in synthesis and biodegradation. Work to date suggests that the reaction is catalyzed by a cofactor not found in other oxygenases, implying a new strategy for oxygen activation. The proposed studies build on the very significant progress that has been made in the previous funding period, and focus on: elucidation of the physical and electronic structure of dinuclear iron cluster of the active site as well as the mechanism of oxygen activation catalyzed by this center; spectroscopic and kinetic characterization of the several reaction intermediates that have been identified in the catalytic sequence; elucidation of the protein-protein interactions between the three polypeptides of the enzyme that modulate its catalytic activity.