Molecular mechanism of the redox-dependent interaction between NADH-dependent ferredoxin reductase and rieske-type [2Fe-2S] ferredoxin
Molecular mechanism of the redox-dependent interaction between NADH-dependent ferredoxin reductase and rieske-type [2Fe-2S] ferredoxin
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DOI：
10.1016/j.jmb.2007.08.002
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发表时间：
2007-10-19
影响因子：
5.6
通讯作者：
Senda, Toshiya
中科院分区：
文献类型：
--
作者：
Senda, Miki;Kishigami, Shinya;Senda, Toshiya
联苯双加氧酶BphA的电子转移系统，其来源于Acidovorax sp.（正式假单胞菌属）。菌株KKS 102由含FAD的NADH-铁氧还蛋白还原酶（BphA 4）和Rieske型[2Fe-2S]铁氧还蛋白（BphA 3）组成。生物化学研究表明，从NADH到BphA 3的整个电子转移过程包括三个连续的基本电子转移反应，其中BphA 3和BphA 4以氧化还原依赖的方式瞬时相互作用。最初，BphA 4从NADH接收两个电子。然后，还原的BphA 4通过氧化还原依赖的瞬态相互作用将一个电子分别传递到两个BphA 3分子的[2Fe-2S]簇。还原的BphA 3将电子传递到末端加氧酶BphA 1A 2，以支持用于联苯二羟基化的双氧的活化。为了阐明BphA 3和BphA 4之间的顺序反应和氧化还原依赖性相互作用的分子机制，我们确定了生产BphA 3-BphA 4复合物的晶体结构，以及在催化循环中发生的所有氧化还原状态下的游离BphA 3和BphA 4。这些反应中间体的晶体结构表明，每个基本的电子转移诱导一系列的氧化还原依赖的构象变化BphA 3和BphA 4，调节它们之间的相互作用。此外，由前一个电子转移引起的构象变化似乎会引起下一个电子转移。电子转移和诱导的构象变化的相互作用似乎是至关重要的顺序从NADH到BphA 3的电子转移反应。(C)2007爱思唯尔有限公司保留所有权利。
The electron transfer system of the biphenyl dioxygenase BphA, which is derived from Acidovorax sp. (formally Pseudomonas sp.) strain KKS102, is composed of an FAD-containing NADH-ferredoxin reductase (BphA4) and a Rieske-type [2Fe-2S] ferredoxin (BphA3). Biochemical studies have suggested that the whole electron transfer process from NADH to BphA3 comprises three consecutive elementary electron-transfer reactions, in which BphA3 and BphA4 interact transiently in a redox-dependent manner. Initially, BphA4 receives two electrons from NADH. The reduced BphA4 then delivers one electron each to the [2Fe-2S] cluster of the two BphA3 molecules through redox-dependent transient interactions. The reduced BphA3 transports the electron to BphA1A2, a terminal oxygenase, to support the activation of dioxygen for biphenyl dihydroxylation. In order to elucidate the molecular mechanisms of the sequential reaction and the redox-dependent interaction between BphA3 and BphA4, we determined the crystal structures of the productive BphA3-BphA4 complex, and of free BphA3 and BphA4 in all the redox states occurring in the catalytic cycle. The crystal structures of these reaction intermediates demonstrated that each elementary electron transfer induces a series of redox-dependent conformational changes in BphA3 and BphA4, which regulate the interaction between them. In addition, the conformational changes induced by the preceding electron transfer seem to induce the next electron transfer. The interplay of electron transfer and induced conformational changes seems to be critical to the sequential electron-transfer reaction from NADH to BphA3. (C) 2007 Elsevier Ltd. All rights reserved.