Catalytic Mechanisms of Heme-Copper Oxidases

血红素铜氧化酶的催化机制

基本信息

批准号：
6895418
负责人：
MARIAN FABIAN
金额：
$ 25.66万
依托单位：
RICE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-06-01 至 2007-02-28
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Respiratory oxidases are membrane-bound electron-transfer complexes which catalyze the reduction of molecular dioxygen to water and use the associated free energy changes to generate a transmembrane proton gradient. This proton gradient is the primary source of energy for biological free energy in humans. In recent years it has become apparent that most respiratory oxidases are members of a single family, the heme-copper oxidase super-family. Members of this family have a unique bimetallic center composed of heme plus copper; at this center dioxygen is reduced and high affinity ligands are bound. Cytochrome c oxidase (CcO) catalyzes in one enzymatic cycle the oxidation of four equivalents of ferrocytochrome c located on the cytosolic side of the inner mitochondrial membrane and this oxidation is accompanied by the consumption of four protons from the matrix space to complete the formation of two water molecules. The free energy expended in the formation of water is not dissipated but conserved as a trans-membrane proton gradient with a stoichiometry one proton translocated per electron transferred. The complete conversion of oxygen to water proceeds through specific oxy intermediates corresponding to discrete chemical states of the binuclear center. Despite a large body of valuable knowledge that has been accumulated in recent years the chemical nature of certain of these oxy intermediates is still controversial and very little is known about the proton pumping mechanism per se and the involvement of these intermediates in the pumping process. The objective of this proposal is to establish the nature of selected oxy intermediates, their protonation state, the mechanism and the redox stoichiometry of their interconversion, the relation of these intermediates to the proton pumping activity, to test the hypothesis that the conservation of electroneutrality at the binuclear center is a fundamental requirement and to characterize the mechanism of ligand interaction(s). To address these problems we plan to use isolated mitochondria, purified bovine CcO and CcO incorporated into vesicles. Optical spectroscopy, electron paramagnetic resonance with rapid quenching kinetics, magnetic and natural circular dichroism, resonance Raman spectroscopy, stopped-flow kinetics, and several biochemical methods will be used to accomplish these goals.

描述（由申请人提供）：呼吸道氧化酶是膜结合的电子转移复合物，催化分子二氧化物的还原浇水并使用相关的自由能变化来产生跨膜质子梯度。该质子梯度是能量的主要来源人类的生物自由能。近年来，显然大多数呼吸道氧化酶是单个家族的成员，是血红素的氧化酶氧化酶超级家庭。这个家庭的成员有一个独特的双金属中心由血红素加铜组成；在这个中心，二氧化物减少了亲和力配体是绑定的。细胞色素C氧化酶（CCO）催化酶促循环的四个等效物的氧化位置在内部线粒体膜的胞质侧，这种氧化为伴随着从矩阵空间到的四个质子的消耗完成两个水分子的形成。自由能在水的形成不是消散，而是作为跨膜质子保守的具有化学计量的梯度，每个电子转移的质子一个易位。氧气向水的完全转化是通过特定的氧气进行的与双核的离散化学状态相对应的中间体中心。尽管已经积累了很多宝贵的知识近年来，这些氧中间体的某些化学性质仍然是关于质子泵送机制，有争议的且知之甚少 SE和这些中间体参与抽水过程。这该提议的目的是建立选定的氧气的性质中间体，质子化状态，机制和氧化还原它们的互转换的化学计量法，这些中间体与质子抽水活动，以检验以下假设双核中心的电压是基本要求，表征配体相互作用的机制。解决这些问题我们计划使用孤立的线粒体，纯化的牛CCO和CCO Incorporated 进入囊泡。光谱，电子顺磁共振迅速淬灭动力学，磁性和自然圆二色性，共振拉曼光谱学，停止流动动力学和几种生化方法将是用于实现这些目标。

项目成果

期刊论文数量（14）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Proton involvement in the transition from the "peroxy" to the ferryl intermediate of cytochrome c oxidase.

质子参与细胞色素c氧化酶从“过氧”到ferryl中间体的转变。

DOI：
10.1021/bi002373i
发表时间：
2001
期刊：
Biochemistry
影响因子：
2.9
作者：
Fabian,M;Palmer,G
通讯作者：
Palmer,G

The contributions of G.T. (Jerry) Babcock to our understanding of cytochrome oxidase.

G.T.的贡献

DOI：
10.1016/j.bbabio.2003.05.001
发表时间：
2004
期刊：
Biochimica et biophysica acta
影响因子：
0
作者：
Palmer,Graham
通讯作者：
Palmer,Graham

Two sites of interaction of anions with cytochrome a in oxidized bovine cytochrome c oxidase.

氧化牛细胞色素 c 氧化酶中阴离子与细胞色素 a 相互作用的两个位点。

DOI：
10.1074/jbc.m311834200
发表时间：
2004
期刊：
The Journal of biological chemistry
影响因子：
0
作者：
Fabian,Marian;Jancura,Daniel;Palmer,Graham
通讯作者：
Palmer,Graham

The reactivity of alpha-hydroxyhaem and verdohaem bound to haem oxygenase-1 to dioxygen and sodium dithionite.

α-羟基血红素和维多血红素与血红素加氧酶-1 结合，生成双氧和连二亚硫酸钠。

DOI：
10.1046/j.1432-1033.2002.03230.x
发表时间：
2002
期刊：
European journal of biochemistry
影响因子：
0
作者：
Sakamoto,Hiroshi;Omata,Yoshiaki;Hayashi,Shunsuke;Harada,Saori;Palmer,Graham;Noguchi,Masato
通讯作者：
Noguchi,Masato

A kinetic study of the mechanism of conversion of alpha-hydroxyheme to verdoheme while bound to heme oxygenase.

与血红素加氧酶结合时α-羟基血红素转化为绿血红素机制的动力学研究。

DOI：
10.1016/j.bbrc.2005.08.176
发表时间：
2005
期刊：
Biochemical and biophysical research communications
影响因子：
3.1
作者：
Sakamoto,Hiroshi;Takahashi,Kenichi;Higashimoto,Yuichiro;Harada,Saori;Palmer,Graham;Noguchi,Masato
通讯作者：
Noguchi,Masato