New enzymatic pathways for the reduction of reactive oxygen species in Entamoeba histolytica
New enzymatic pathways for the reduction of reactive oxygen species in Entamoeba histolytica
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DOI：
10.1016/j.bbagen.2015.02.010
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发表时间：
2015-06-01
影响因子：
3
通讯作者：
Arias, Diego G.
中科院分区：
文献类型：
--
作者：
Cabeza, Matias S.;Guerrero, Sergio A.;Arias, Diego G.
背景资料：溶组织内阿米巴是一种肠道寄生虫，是阿米巴病的病原体，在组织侵入过程中暴露于大量高毒性活性氧和氮。尽管尚未鉴定出它们的生理还原剂，但已在这种人类病原体中鉴定出黄二铁蛋白和红红素。方法：本工作涉及生化研究，以更好地了解红氧还蛋白还原酶和两种铁氧还蛋白的动力学和结构特性。来自E.结果：我们补充了E.溶组织剂我们表征了一种具有红氧还蛋白还原酶活性的新型阿米巴蛋白，该蛋白能够催化异源红氧还蛋白、阿米巴红红素和黄二铁蛋白的NAD（P）H依赖性还原，但不能催化铁氧还蛋白。此外，该蛋白质表现出NAD（P）H氧化酶活性，其从分子氧产生过氧化氢。我们描述了如何不同的铁氧化还原蛋白也是有效的还原底物两个flavodiiron蛋白和ruberrythrin.Conclusions：在此表征的酶系统可能有助于在体内解毒的O-2和H2 O2，起着关键作用的寄生虫防御反应性氧化剂物种。一般意义：据我们所知，这是第一次表征真核红氧还蛋白还原酶，包括一个新的动力学研究依赖于铁氧还蛋白减少flavodiiron和rubretythrin蛋白。(C)2015 Elsevier B. V.版权所有。
Background: Entamoeba histolytica, an intestinal parasite that is the causative agent of amoebiasis, is exposed to elevated amounts of highly toxic reactive oxygen and nitrogen species during tissue invasion. A flavodiiron protein and a rubrerythrin have been characterized in this human pathogen, although their physiological reductants have not been identified.Methods: The present work deals with biochemical studies performed to reach a better understanding of the kinetic and structural properties of rubredoxin reductase and two ferredoxins from E. histolytica.Results: We complemented the characterization of two different metabolic pathways for O-2 and H2O2 detoxification in E. histolytica. We characterized a novel amoebic protein with rubredoxin reductase activity that is able to catalyze the NAD(P)H-dependent reduction of heterologous rubredoxins, amoebic rubretythrin and flavodiiron protein but not ferredoxins. In addition, the protein exhibited an NAD(P)H oxidase activity, which generates hydrogen peroxide from molecular oxygen. We describe how different ferredoxins were also efficient reducing substrates for both flavodiiron protein and rubrerythrin.Conclusions: The enzymatic systems herein characterized could contribute to the in vivo detoxification of O-2 and H2O2, playing a key role for the parasite defense against reactive oxidant species. General significance: To the best of our knowledge this is the first characterization of a eukaryotic rubredoxin reductase, including a novel kinetic study on ferredoxin-dependent reduction of flavodiiron and rubretythrin proteins. (C) 2015 Elsevier B.V. All rights reserved.