The Di-Iron Protein YtfE Is a Nitric Oxide-Generating Nitrite Reductase Involved in the Management of Nitrosative Stress.
The Di-Iron Protein YtfE Is a Nitric Oxide-Generating Nitrite Reductase Involved in the Management of Nitrosative Stress.
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DOI：
10.1021/jacs.1c12407
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发表时间：
2022-04-27
影响因子：
15
通讯作者：
Le Brun, Nick E.
中科院分区：
文献类型：
--
作者：
Crack, Jason C.;Balasiny, Basema K.;Bennett, Sophie P.;Rolfe, Matthew D.;Froes, Afonso;MacMillan, Fraser;Green, Jeffrey;Cole, Jeffrey A.;Le Brun, Nick E.
先前表征的亚硝酸盐还原酶分为三类：含铁血红素酶（NirBD）、细胞色素c血红蛋白（NrfA和NirS）和含铜酶（NirK）。我们在这里表明，二铁蛋白YtfE代表了一种与生理相关的新型亚硝酸盐还原酶。YtfE的一些功能已经被提出，包括提供铁来修复被亚硝化应激损伤的铁硫簇，从亚硝基化铁中释放一氧化氮（NO），并将NO还原为一氧化二氮（N2O）。在这里，体内报告试验证实，大肠杆菌YtfE增加了亚硝酸盐的细胞质NO产量。光谱和质谱研究表明，当从亚硝酸盐补充而不是硝酸盐补充的培养中分离时，YtfE的二铁位点以混合形式存在，包括亚硝基化和亚硝酸盐结合。在二亚铁YtfE中加入亚硝酸盐可使YtfE发生亚硝基化，并释放NO。亚硝酸盐的还原动力学取决于还原剂的性质；对于二铁形式，测量的最低Km为~ 90 μM，完全在细胞内亚硝酸盐浓度范围内。邻近的二半胱氨酸基序，位于YtfE的n端结构域，被证明在电子传递到二铁中心的过程中起作用。值得注意的是，YtfE表现出非常低的NO还原酶活性，并且只能在其双铁中心受损的情况下作为载铁还蛋白重建的铁供体。因此，YtfE是一种高亲和力、低容量的亚硝酸盐还原酶，我们认为它通过与共调节的no消耗酶Hmp和Hcp结合来缓解亚硝酸盐应激。
Previously characterized nitrite reductases fall into three classes: siroheme-containing enzymes (NirBD), cytochrome c hemoproteins (NrfA and NirS), and copper-containing enzymes (NirK). We show here that the di-iron protein YtfE represents a physiologically relevant new class of nitrite reductases. Several functions have been previously proposed for YtfE, including donating iron for the repair of iron–sulfur clusters that have been damaged by nitrosative stress, releasing nitric oxide (NO) from nitrosylated iron, and reducing NO to nitrous oxide (N2O). Here, in vivo reporter assays confirmed that Escherichia coli YtfE increased cytoplasmic NO production from nitrite. Spectroscopic and mass spectrometric investigations revealed that the di-iron site of YtfE exists in a mixture of forms, including nitrosylated and nitrite-bound, when isolated from nitrite-supplemented, but not nitrate-supplemented, cultures. Addition of nitrite to di-ferrous YtfE resulted in nitrosylated YtfE and the release of NO. Kinetics of nitrite reduction were dependent on the nature of the reductant; the lowest Km, measured for the di-ferrous form, was ∼90 μM, well within the intracellular nitrite concentration range. The vicinal di-cysteine motif, located in the N-terminal domain of YtfE, was shown to function in the delivery of electrons to the di-iron center. Notably, YtfE exhibited very low NO reductase activity and was only able to act as an iron donor for reconstitution of apo-ferredoxin under conditions that damaged its di-iron center. Thus, YtfE is a high-affinity, low-capacity nitrite reductase that we propose functions to relieve nitrosative stress by acting in combination with the co-regulated NO-consuming enzymes Hmp and Hcp.
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DOI：
10.1074/jbc.m115.693192
发表时间：
2016-04-15
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Crack JC;Svistunenko DA;Munnoch J;Thomson AJ;Hutchings MI;Le Brun NE
通讯作者：
Le Brun NE
影响因子：
2.9
作者：
Anderson, LJ;Richardson, DJ;Butt, JN
通讯作者：
Butt, JN
影响因子：
3.9
作者：
Büsch, A;Strube, K;Cramm, R
通讯作者：
Cramm, R
影响因子：
3
作者：
Bou-Abdallah, Fadi;Chasteen, N. Dennis
通讯作者：
Chasteen, N. Dennis
影响因子：
3.9
作者：
Chen, Kelvin H. -C.;Chuankhayan, Phirnonphan;Chan, Sunney I.
通讯作者：
Chan, Sunney I.