A Small Family of Chloroplast Atypical Thioredoxins
A Small Family of Chloroplast Atypical Thioredoxins
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DOI：
10.1104/pp.108.128314
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发表时间：
2009-03-01
期刊：
影响因子：
7.4
通讯作者：
Danon, Avihai
中科院分区：
文献类型：
--
作者：
Dangoor, Inbal;Peled-Zehavi, Hadas;Danon, Avihai
调节性二硫键的减少和形成是叶绿体中的关键信号元件。氧化还原酶硫氧还蛋白 (Trx) 超家族的成员在这些过程中发挥着重要作用。我们在拟南芥 (Arabidopsis thaliana) 中鉴定了一小类植物特异性 Trx，它们富含半胱氨酸和组氨酸残基，并以可变的非规范氧化还原活性位点为代表。我们发现三个选定的家族成员的氧化还原中点电位的降低明显小于经典 Trxs。亚细胞定位分析表明所有蛋白质都定位于叶绿体。选定的成员对叶绿体 2-半胱氨酸过氧化还原蛋白 A 表现出高活性（取决于二硫醇电子供体），而对叶绿体 NADP-苹果酸脱氢酶活性较差。家庭成员的表达谱表明他们具有不同的角色。非典型 Trx 的中间氧化还原中点电位值可能意味着具有调节二硫化物调节叶绿体蛋白氧化还原状态功能的适应性。
The reduction and the formation of regulatory disulfide bonds serve as a key signaling element in chloroplasts. Members of the thioredoxin (Trx) superfamily of oxidoreductases play a major role in these processes. We have characterized a small family of plant-specific Trxs in Arabidopsis (Arabidopsis thaliana) that are rich in cysteine and histidine residues and are typified by a variable noncanonical redox active site. We found that the redox midpoint potential of three selected family members is significantly less reducing than that of the classic Trxs. Assays of subcellular localization demonstrated that all proteins are localized to the chloroplast. Selected members showed high activity, contingent on a dithiol electron donor, toward the chloroplast 2-cysteine peroxiredoxin A and poor activity toward the chloroplast NADP-malate dehydrogenase. The expression profile of the family members suggests that they have distinct roles. The intermediate redox midpoint potential value of the atypical Trxs might imply adaptability to function in modulating the redox state of chloroplast proteins with regulatory disulfides.