Binding of exogenous cyanide reveals new active-site states in [FeFe] hydrogenases.
Binding of exogenous cyanide reveals new active-site states in [FeFe] hydrogenases.
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DOI：
10.1039/d2sc06098a
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发表时间：
2023-03-15
期刊：
影响因子：
8.4
通讯作者：
中科院分区：
文献类型：
--
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[FeFe]氢化酶是用于氢转化的高效金属酶。它们的活性中心辅因子（H-簇）由典型的[4Fe-4S]簇（[4Fe-4S]H）连接到独特的有机金属二铁子簇（[2Fe]H）组成。在[2Fe]H中，两个Fe离子被一个桥连的2-氮杂丙烷-1，3-二硫醇盐（ADT）配体、三个CO和两个CN−配体配位，在一个Fe上留下一个开放的配位位点，底物（H2和H+）以及抑制剂（例如O2、CO、H2S）可以结合在这里。在这里，我们调查两个新的活性位点的状态，积累在[FeFe]氢化酶的变体中的半胱氨酸（Cys）的质子转移途径突变为丙氨酸（Ala）。我们的实验数据，包括原子分辨率的晶体结构和计算支持，表明在这两种状态下，第三个CN−配体与[2Fe]H的顶端位置结合。这些状态可以通过从受损的[2 Fe]H子团簇中“蚕食”CN-以及添加外源CN-来产生。这是第一个详细的光谱和计算表征外源CN−与[FeFe]氢化酶的相互作用。类似的CN−结合态也可以在野生型氢化酶中产生，但不像Cys到Ala变体那样容易形成。这些结果突出了质子转移途径中的第一个氨基酸与活性位点之间的相互作用如何调节配体与开放配位位点的结合并影响H-簇的电子结构。外源氰化物与[FeFe]氢化酶活性中心H-簇的结合稳定了新的活性中心状态，过度氧化的二铁辅因子显示了σ-供体/π-受体相互作用如何影响金属辅因子的电子结构。
[FeFe] hydrogenases are highly efficient metalloenyzmes for hydrogen conversion. Their active site cofactor (the H-cluster) is composed of a canonical [4Fe-4S] cluster ([4Fe-4S]H) linked to a unique organometallic di-iron subcluster ([2Fe]H). In [2Fe]H the two Fe ions are coordinated by a bridging 2-azapropane-1,3-dithiolate (ADT) ligand, three CO and two CN− ligands, leaving an open coordination site on one Fe where substrates (H2 and H+) as well as inhibitors (e.g. O2, CO, H2S) may bind. Here, we investigate two new active site states that accumulate in [FeFe] hydrogenase variants where the cysteine (Cys) in the proton transfer pathway is mutated to alanine (Ala). Our experimental data, including atomic resolution crystal structures and supported by calculations, suggest that in these two states a third CN− ligand is bound to the apical position of [2Fe]H. These states can be generated both by “cannibalization” of CN− from damaged [2Fe]H subclusters as well as by addition of exogenous CN−. This is the first detailed spectroscopic and computational characterisation of the interaction of exogenous CN− with [FeFe] hydrogenases. Similar CN−-bound states can also be generated in wild-type hydrogenases, but do not form as readily as with the Cys to Ala variants. These results highlight how the interaction between the first amino acid in the proton transfer pathway and the active site tunes ligand binding to the open coordination site and affects the electronic structure of the H-cluster. Binding of exogenous cyanide to the active site H-cluster in [FeFe] hydrogenase stabilizes new active-site states with an overoxidized diiron cofactor showing how σ-donor/π-acceptor interactions influence the electronic structure of metallocofactors.
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影响因子：
2.9
作者：
Dou, Y;Olson, JS;IkedaSaito, M
通讯作者：
IkedaSaito, M
影响因子：
16.6
作者：
Duan, Jifu;Senger, Moritz;Winkler, Martin
通讯作者：
Winkler, Martin
影响因子：
15
作者：
Esselborn, Julian;Kertess, Leonie;Happe, Thomas
通讯作者：
Happe, Thomas
影响因子：
15
作者：
Goldet, Gabrielle;Brandmayr, Caterina;Armstrong, Fraser A.
通讯作者：
Armstrong, Fraser A.
DOI：
10.1016/j.bbrc.2010.01.092
发表时间：
2010-03-05
影响因子：
3.1
作者：
Ascenzi, Paolo;di Masi, Alessandra;Coletta, Massimo
通讯作者：
Coletta, Massimo