The metalloenzymes of ammonia-oxidizing bacteria

氨氧化细菌的金属酶

基本信息

批准号：
6953860
负责人：
A ANDREW PACHECO
金额：
$ 21.14万
依托单位：
UNIVERSITY OF WISCONSIN MILWAUKEE
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-09-09 至 2007-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6953860
关键词：
ammonia bacterial proteins bioreactors biotransformation cytochrome c cytochrome oxidase enzyme complex enzyme mechanism gram negative bacteria hydroxylamine metalloenzyme microorganism metabolism nitrites respiratory enzyme soil microbiology

项目摘要

DESCRIPTION (provided by applicant): The goal of the proposed research is to elucidate the function and reactivity of hydroxylamine-cytochrome c554 oxidoreductase (HAO), a remarkably complex respiratory enzyme from the bacterium Nm. europaea. A series of novel pulsed-laser techniques will be used to generate postulated intermediates of HAO's catalytic pathway, and a combination of electrochemical and computational techniques will be used to investigate the properties of the enzyme's many redox-active centers. The net oxidation of ammonia to nitrite by oxygen is the only process whereby Nm. europaea can extract usable energy from the surroundings. HAO catalyzes a critical step in this process, the 4-electron oxidation of hydroxylamine to nitrite. Bacteriologically-mediated oxidation of ammonia to nitrite is an important public and environmental health issue in all parts of the country where agriculture is a significant part of the economy. Nitrite is a potential precursor for carcinogenic N-nitroso compounds, and for the potent greenhouse gas nitrous oxide. As much as 50% of ammonia fertilizer may be oxidized to nitrite by soil-inhabiting bacteria before it can reach its target crops, and because nitrite is highly soluble, it readily contaminates surrounding rivers and groundwater. Under carefully controlled conditions bacteriologically-mediated ammonia oxidation can also benefit public health. Mixtures of Nm. europaea, and complementary bacteria that reduce nitrite to nitrogen, are used in sewage treatment plants to eliminate excess ammonia from waste water. The research being proposed, which aims at understanding in detail how HAO works, may suggest ideas about how to manage ammonia oxidation in agricultural settings and sewage treatment, for maximum benefit to public and environmental health. The project may also provide important insights into the redox chemistry of physiologically important enzymatic metal-nitrogen species that will be of interest to the medical research community.

描述（由申请人提供）：拟议研究的目标是阐明羟胺细胞色素 c554 氧化还原酶（HAO）的功能和反应性，HAO 是一种来自细菌 Nm 的非常复杂的呼吸酶。欧洲。一系列新颖的脉冲激光技术将用于生成 HAO 催化途径的假定中间体，并且电化学和计算技术的组合将用于研究该酶的许多氧化还原活性中心的特性。氨被氧气净氧化为亚硝酸盐是 Nm 的唯一过程。欧洲可以从周围环境中提取可用的能源。 HAO 催化该过程中的关键步骤，即羟胺向亚硝酸盐的四电子氧化。在农业是经济重要组成部分的全国各地，细菌介导的氨氧化成亚硝酸盐是一个重要的公共和环境健康问题。亚硝酸盐是致癌性 N-亚硝基化合物和强效温室气体一氧化二氮的潜在前体。多达50%的氨肥在到达目标作物之前可能会被土壤中的细菌氧化成亚硝酸盐，而且由于亚硝酸盐具有高溶解性，很容易污染周围的河流和地下水。在严格控制的条件下，细菌介导的氨氧化也有利于公众健康。 Nm 的混合物。 Europaea 和将亚硝酸盐还原为氮的补充细菌被用于污水处理厂，以消除废水中过量的氨。正在提议的研究旨在详细了解 HAO 的工作原理，可能会提出有关如何管理农业环境和污水处理中氨氧化的想法，以最大限度地造福公众和环境健康。该项目还可能提供对生理上重要的酶金属氮物质的氧化还原化学的重要见解，这将引起医学研究界的兴趣。