Generation of H 2 S from Thiol-Dependent NO Reactivity of Model [4Fe-4S] Cluster and Roussin’s Black Anion
Generation of H 2 S from Thiol-Dependent NO Reactivity of Model [4Fe-4S] Cluster and Roussin’s Black Anion
复制标题
从 [4Fe-4S] 模型簇和 Roussin 黑阴离子的硫醇依赖性 NO 反应性生成 H 2 S
DOI：
10.1021/acs.inorgchem.1c01328
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发表时间：
2021
影响因子：
4.6
通讯作者：
Kim, Eunsuk
中科院分区：
文献类型：
--
作者：
Oakley, Kady M.;Zhao, Ziyi;Lehane, Ryan L.;Ma, Ji;Kim, Eunsuk
铁硫簇合物（Fe-S）是生物系统中一氧化氮（NO）的靶分子。作为对蛋白质结合研究的补充，合成模型提供了一个平台来研究根据受控的反应环境产生什么样的铁亚硝基化产物和副产物。我们先前已经展示了一个模型[2Fe-2S]系统，该系统在巯基存在下，在与硫化氢（H2S）（另一种重要的气体传递剂）的亚硝基化沿着时产生二亚硝酰基铁络合物（DNIC），并假设与[4Fe-4S]簇有类似的反应模式，该簇在生物和合成系统中很大程度上产生不一致的反应产物。铁蛋白黑阴离子[Fe 4（μ3-S）3（NO）7]−是合成的[4Fe-4S]簇与NO的反应产物。在这里，我们提出了一种新的反应性，用于合成[4Fe-4S]簇在硫醇和硫醇盐存在下的亚硝基化。[Et 4 N]2[Fe 4S 4（SPh）4]（1）在过量PhSH存在下被亚硝基化以生成H2S和“RBA样”中间体，当该中间体与[NEt 4][SPh]进一步反应时生成{Fe（NO）2}9DNIC，[Et 4 N][Fe（NO）2（SPh）2]（2）。这种“RBA样”中间体证明难以分离，但在基于IR IR（NO）伸缩频率的硫醇存在下与RBA具有惊人的相似性。令人惊讶的是，当用RBA和硫醇开始反应时，产生相同的反应产物。类似于1/NO，RBA在硫醇和硫醇盐存在下产生化学计量量的DNIC，同时释放其桥连硫化物作为H2S。这些结果不仅表明RBA可能不是[4Fe-4S] + NO的最终产物，而且RBA与硫醇和硫醇盐具有前所未有的反应性，这可以解释目前围绕鉴定生物亚硝基化Fe-S簇的挑战。
Iron–sulfur clusters (Fe–S) have been well established as a target for nitric oxide (NO) in biological systems. Complementary to protein-bound studies, synthetic models have provided a platform to study what iron nitrosylated products and byproducts are produced depending on a controlled reaction environment. We have previously shown a model [2Fe-2S] system that produced a dinitrosyl iron complex (DNIC) upon nitrosylation along with hydrogen sulfide (H2S), another important gasotransmitter, in the presence of thiol, and hypothesized a similar reactivity pattern with [4Fe-4S] clusters which have largely produced inconsistent reaction products across biological and synthetic systems. Roussin’s black anion (RBA), [Fe4(μ3-S)3(NO)7]−, is a previously established reaction product from synthetic [4Fe-4S] clusters with NO. Here, we present a new reactivity for the nitrosylation of a synthetic [4Fe-4S] cluster in the presence of thiol and thiolate. [Et4N]2[Fe4S4(SPh)4] (1) was nitrosylated in the presence of excess PhSH to generate H2S and an “RBA-like” intermediate that when further reacted with [NEt4][SPh] produced a {Fe(NO)2}9DNIC, [Et4N][Fe(NO)2(SPh)2] (2). This “RBA-like” intermediate proved difficult to isolate but shares striking similarities to RBA in the presence of thiol based on IR υ(NO)stretching frequencies. Surprisingly, the same reaction products were produced when the reaction started with RBA and thiol. Similar to1/NO, RBA in the presence of thiol and thiolate generates stoichiometric amounts of DNIC while releasing its bridging sulfides as H2S. These results suggest not only that RBA may not be the final product of [4Fe-4S] + NO but also that RBA has unprecedented reactivity with thiols and thiolates which may explain current challenges around identifying biological nitrosylated Fe–S clusters.