A ternary mechanism for NADH oxidation by positively charged electron acceptors, catalyzed at the flavin site in respiratory complex I
A ternary mechanism for NADH oxidation by positively charged electron acceptors, catalyzed at the flavin site in respiratory complex I
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DOI：
10.1016/j.febslet.2011.05.065
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发表时间：
2011-07-21
期刊：
影响因子：
3.5
通讯作者：
Hirst, Judy
中科院分区：
文献类型：
--
作者：
Birrell, James A.;King, Martin S.;Hirst, Judy
复合物 I（NADH：泛醌氧化还原酶）中的黄素单核苷酸催化 NADH 氧化、O(2) 还原为超氧化物，以及几个“人工”电子受体的还原。在这里，我们证明带正电的电子受体百草枯和六氨合钌(III)通过一种不寻常的三元机制与复合物I中核苷酸结合的还原黄素发生反应。 NADH、ATP、ADP 和 ADP-核糖刺激反应，表明带正电荷的受体与其带负电荷的磷酸盐相互作用。我们的百草枯还原机制定义了复合物 I（通过氧化还原循环）产生超氧化物的新机制；与直接减少 O(2) 相比，高 NADH 浓度会刺激而不是抑制该速率。 (C) 2011 年欧洲生化学会联合会。由 Elsevier B.V. 出版。保留所有权利。
The flavin mononucleotide in complex I (NADH: ubiquinone oxidoreductase) catalyzes NADH oxidation, O(2) reduction to superoxide, and the reduction of several 'artificial' electron acceptors. Here, we show that the positively-charged electron acceptors paraquat and hexaammineruthenium(III) react with the nucleotide-bound reduced flavin in complex I, by an unusual ternary mechanism. NADH, ATP, ADP and ADP-ribose stimulate the reactions, indicating that the positively-charged acceptors interact with their negatively-charged phosphates. Our mechanism for paraquat reduction defines a new mechanism for superoxide production by complex I (by redox cycling); in contrast to direct O(2) reduction the rate is stimulated, not inhibited, by high NADH concentrations. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.