Redox-dependent complex formation by an ATP-dependent activator of the corrinoid/iron-sulfur protein
Redox-dependent complex formation by an ATP-dependent activator of the corrinoid/iron-sulfur protein
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DOI：
10.1073/pnas.1117126109
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发表时间：
2012-04-03
影响因子：
11.1
通讯作者：
Dobbek, Holger
中科院分区：
文献类型：
--
作者：
Hennig, Sandra E.;Jeoung, Jae-Hun;Dobbek, Holger
运动、细胞分裂、蛋白质生物合成、逆着电化学梯度的电子转移以及更多的过程都依赖于与ATP水解耦合的能量转换。具有低还原电位（E-0' < -500 mV）的金属位点的还原是可能的，通过将能量向上的电子转移与ATP的水解连接。类科里醇-铁/硫蛋白（CoFeSP）在还原性乙酰辅酶A途径中发挥作用，将与甲基转移酶结合的甲基四氢叶酸的甲基转移到乙酰辅酶A合酶的[Ni-Ni-Fe 4S 4]簇。CoFeSP的甲基化仅发生在低电位的Co（I）状态，其可以零星地氧化成无活性的Co（II）状态，使得其还原再活化是必要的。在这里，我们表明，一个开放阅读框近端的CoFeSP的结构基因编码的ATP依赖性还原激活CoFeSP。我们的生物化学和结构分析揭示了一种独特类型的还原激活剂，不同于电子转移ATP酶，发现减少钼铁固氮酶和2-羟酰辅酶A脱氢酶。CoFeSP激活剂含有一个ASKHA结构域（乙酸和糖激酶、Hsp 70和肌动蛋白），该结构域含有ATP结合位点，该位点也存在于2-羟酰基- CoA脱氢酶的激活剂中，以及一个铁氧还蛋白样[2Fe-2S]簇结构域作为电子供体。CoFeSP与其激活剂之间的复合物形成取决于CoFeSP的氧化态，这为实现两种氧化还原蛋白之间的单向电子转移的独特策略提供了证据。
Movement, cell division, protein biosynthesis, electron transfer against an electrochemical gradient, and many more processes depend on energy conversions coupled to the hydrolysis of ATP. The reduction of metal sites with low reduction potentials (E-0' < -500 mV) is possible by connecting an energetical uphill electron transfer with the hydrolysis of ATP. The corrinoid-iron/sulfur protein (CoFeSP) operates within the reductive acetyl-CoA pathway by transferring a methyl group from methyltetrahydrofolate bound to a methyltransferase to the [Ni-Ni-Fe4S4] cluster of acetyl-CoA synthase. Methylation of CoFeSP only occurs in the low-potential Co(I) state, which can be sporadically oxidized to the inactive Co(II) state, making its reductive reactivation necessary. Here we show that an open-reading frame proximal to the structural genes of CoFeSP encodes an ATP-dependent reductive activator of CoFeSP. Our biochemical and structural analysis uncovers a unique type of reductive activator distinct from the electron-transferring ATPases found to reduce the MoFe-nitrogenase and 2-hydroxyacyl- CoA dehydratases. The CoFeSP activator contains an ASKHA domain (acetate and sugar kinases, Hsp70, and actin) harboring the ATP-binding site, which is also present in the activator of 2-hydroxyacyl- CoA dehydratases and a ferredoxin-like [2Fe-2S] cluster domain acting as electron donor. Complex formation between CoFeSP and its activator depends on the oxidation state of CoFeSP, which provides evidence for a unique strategy to achieve unidirectional electron transfer between two redox proteins.