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Mechanism of pyruvate ferredoxin oxidoreductase and role of the (4Fe-4S) cluster of the corrinoid iron sulfur protein in acetyl COA synthesis by the Wood Ljungdahl pathway.

机译：丙酮酸铁氧还蛋白氧化还原酶的机理以及类固醇铁硫蛋白的（4Fe-4S）簇在Wood Ljungdahl途径合成乙酰COA中的作用。

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Pyruvate ferredoxin oxidoreductase (PFOR) catalyzes the oxidative decarboxylation of pyruvate to acetyl CoA and CO{dollar}sb2.{dollar} By using rapid freeze quench EPR and stopped-flow spectroscopy the three elementary steps that constitute the first reductive half reaction of the PFOR mechanism were elucidated. A hydroxyethyl-TPP radical was identified and characterized as a transient intermediate, and for the first time the kinetic competence of this substrate-derived radical was demonstrated.; The CO{dollar}sb2{dollar} produced in the PFOR reaction was shown to be reduced to CO by CODH/ACS; subsequently, the CO generated binds in the ACS active site at a unique metal center to form a paramagnetic adduct the nickel iron carbon species. This bound carbonyl group then combines with a bound methyl group and coenzyme A to generate a third molecule of acetyl CoA. Two common intermediates were shown to be formed in acetyl CoA synthesis from CO{dollar}sb2{dollar}: CO and the paramagnetic nickel iron carbon species making the Wood Ljungdahl pathway the first pathway in which CO is produced and then used as a metabolic intermediate.; Both PFOR and CODH/ACS were also shown to be able to reduce protons to H{dollar}sb2{dollar} and at much lower rates, oxidize H{dollar}sb2{dollar} to protons and electrons. PFOR and CODH/ACS when incubated with their substrates/electron donors displayed self oxidation in the absence of an electron acceptor. The observed level of hydrogenase activity is physiologically relevant because it accounts for the rate of hydrogen production by growing cultures of Clostridium thermoaceticum.; Another protein the corrinoid iron sulfur protein (CFeSP) which contains a cobalt ion housed in a corrinoid cofactor and an iron sulfur cluster catalyzes two key steps in the Wood Ljungdahl pathway. We have elucidated the role of the (4Fe-4S) cluster by site directed mutagenesis, and have demonstrated that it is required only in the reductive activation cycle that couples the oxidation of substrates like CO to the reduction of Co{dollar}sp{lcub}+2{rcub}.{dollar}

机译：丙酮酸铁氧还蛋白氧化还原酶（PFOR）催化丙酮酸氧化脱羧为乙酰CoA和CO {dollar} sb2。{dollar}通过快速冷冻猝灭EPR和停止流光谱学，这三个基本步骤构成了PFOR的第一个还原性半反应阐明了机理。鉴定了羟乙基-TPP自由基并将其表征为过渡中间体，并且首次证明了该底物衍生的自由基的动力学能力。 PFOR反应中产生的CO {sb2sb2 {美元}被CODH / ACS还原为CO。随后，所产生的CO在独特的金属中心的ACS活性位点结合，形成镍铁碳物种的顺磁性加合物。然后，该结合的羰基与结合的甲基和辅酶A结合以产生乙酰辅酶A的第三分子。已显示由CO {dollar} sb2 {dollar}在乙酰基CoA合成中形成了两种常见的中间体：CO和顺磁性镍铁碳物种使Wood Ljungdahl途径成为产生CO并随后用作代谢中间体的第一个途径。;还显示了PFOR和CODH / ACS均能够将质子还原为H {sb2 {dollar}，并且以低得多的速率将H {slb2 {dollar}氧化为质子和电子。 PFOR和CODH / ACS与底物/电子供体一起孵育时，在没有电子受体的情况下会表现出自氧化作用。所观察到的氢化酶活性水平在生理上是相关的，因为它解释了热乙酸梭菌培养物产生氢的速率。另一种蛋白质是类rinrinoid铁硫蛋白（CFeSP），它包含一个存放在类corrinoid辅因子中的钴离子和一个铁硫簇，催化Wood Ljungdahl途径中的两个关键步骤。我们已经通过定点诱变阐明了（4Fe-4S）簇的作用，并证明仅在还原活化循环中才需要它，该循环将底物（如CO）的氧化与还原Co {dollar} sp {lcub } +2 {rcub}。{dollar}

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作者
Menon, Saurabh Prabhakar.;
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作者单位

The University of Nebraska - Lincoln.;

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授予单位 The University of Nebraska - Lincoln.;
学科 Chemistry Biochemistry.
学位 Ph.D.
年度 1997
页码 169 p.
总页数 169
原文格式 PDF
正文语种 eng
中图分类生物化学;
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专利

1. Mechanism of transfer of the methyl group from (6S)-methyltetrahydrofolate to the corrinoid/iron-sulfur protein catalyzed by the methyltransferase from Clostridium thermoaceticum: a key step in the Wood-Ljungdahl pathway of acetyl-CoA synthesis. [J] . Seravalli J, Zhao S, Ragsdale SW Biochemistry . 1999,第18期

机译：（6S）-甲基四氢叶酸将甲基转移至热乙酸梭菌的甲基转移酶催化的类固醇/铁硫蛋白的转移机理：这是乙酰辅酶A合成的Wood-Ljungdahl途径中的关键步骤。
2. The roles of coenzyme A in the pyruvate:ferredoxin oxidoreductase reaction mechanism: rate enhancement of electron transfer from a radical intermediate to an iron-sulfur cluster. [J] . Furdui C, Ragsdale SW Biochemistry . 2002,第31期

机译：辅酶A在丙酮酸：铁氧还蛋白氧化还原酶反应机理中的作用：加快电子从自由基中间体到铁硫簇的转移速率。
3. Role of the [4Fe-4S] cluster in reductive activation of the cobalt center of the corrinoid iron-sulfur protein from Clostridium thermoaceticum during acetate biosynthesis [J] . Menon S., Ragsdale SW. Biochemistry . 1998,第16期

机译：[4Fe-4S]团簇在乙酸生物合成过程中在热乙酸梭菌中还原类固醇铁硫蛋白的钴中心的活化中的作用
4. THE ARABIDOPSIS CHLOROPLASTIC NifU-LIKE PROTEIN ATCNFU CAN ACT AS AN IRON-SULFUR CLUSTER SCAFFOLD PROTEIN AND IS REQUIRED FOR BIOGENESIS OF FERREDOXIN AND PHOTOSYSTEM I [C] . Toshiki Yabe, Kozo Morimoto, Shingo Kikuchi, International Congress of Photosynthesis . 2005

机译：拟南芥叶状蛋白样蛋白ATCNFU可以作为铁硫簇支架蛋白，并且是福兰昔林和照相的生物发生
5. Iron-sulfur cluster biosynthesis: Iron-sulfur cluster transfer from holo ISU and ISA to apo ferredoxin. [D] . Wu, Shu-Pao. 2004

机译：铁硫团簇的生物合成：铁硫团簇从整体ISU和ISA转移到载脂铁氧还蛋白上。
6. Structural insights into methyltransfer reactions of a corrinoid iron–sulfur protein involved in acetyl-CoA synthesis [O] . Tatiana Svetlitchnaia, Vitali Svetlitchnyi, Ortwin Meyer, 2006

机译：对参与乙酰辅酶A合成的类铁蛋白铁硫蛋白的甲基转移反应的结构见解
7. Structural insights into methyltransfer reactions of a corrinoid iron–sulfur protein involved in acetyl-CoA synthesis [O] . Svetlitchnaia, Tatiana, Svetlitchnyi, Vitali, Meyer, Ortwin, 2006

机译：对参与乙酰辅酶A合成的类铁蛋白铁硫蛋白的甲基转移反应的结构见解

Mechanism of pyruvate ferredoxin oxidoreductase and role of the (4Fe-4S) cluster of the corrinoid iron sulfur protein in acetyl COA synthesis by the Wood Ljungdahl pathway.

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