Calredoxin represents a novel type of calcium-dependent sensor-responder connected to redox regulation in the chloroplast.
Calredoxin represents a novel type of calcium-dependent sensor-responder connected to redox regulation in the chloroplast.
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DOI：
10.1038/ncomms11847
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发表时间：
2016-06-14
影响因子：
16.6
通讯作者：
Hippler M
中科院分区：
文献类型：
--
作者：
Hochmal AK;Zinzius K;Charoenwattanasatien R;Gäbelein P;Mutoh R;Tanaka H;Schulze S;Liu G;Scholz M;Nordhues A;Offenborn JN;Petroutsos D;Finazzi G;Fufezan C;Huang K;Kurisu G;Hippler M
钙(Ca~(2+))和氧化还原信号在从古生物到真核生物的驯化过程中起着重要的作用。在这里，我们鉴定了莱茵衣藻中一种独特的蛋白质，它具有整合钙离子和氧化还原相关信号的能力。该蛋白被命名为钙氧还蛋白(CRX)，它结合了四个钙离子结合的EF-HAND和一个硫氧还蛋白(TRX)结构域。CRX的晶体结构，在1.6 ä分辨率下，揭示了与钙离子结合的EF-HANDS的不寻常的钙调蛋白折叠，它通过结构域间通信路径与具有酶活性的Trx结构域连接在一起。CRX定位于叶绿体，并与叶绿体2-半胱氨酸过氧化还蛋白(PRX1)相互作用。Ca~(2+)与CRX的结合是其TRX活性和PRX1有效结合和还原的关键。因此，CRX代表了一类新的依赖于钙离子的“传感器-反应”蛋白。CRX含量显著减少的基因工程衣藻菌株显示出光合作用电子传递的改变，并在氧化应激反应中受到影响，这支持了CRX在胁迫驯化中的作用。钙和氧化还原信号在适应过程中起着重要作用。在这里，作者描述了莱茵衣藻的一种蛋白质，它可以整合钙和氧化还原相关的信号。
Calcium (Ca2+) and redox signalling play important roles in acclimation processes from archaea to eukaryotic organisms. Herein we characterized a unique protein from Chlamydomonas reinhardtii that has the competence to integrate Ca2+- and redox-related signalling. This protein, designated as calredoxin (CRX), combines four Ca2+-binding EF-hands and a thioredoxin (TRX) domain. A crystal structure of CRX, at 1.6 Å resolution, revealed an unusual calmodulin-fold of the Ca2+-binding EF-hands, which is functionally linked via an inter-domain communication path with the enzymatically active TRX domain. CRX is chloroplast-localized and interacted with a chloroplast 2-Cys peroxiredoxin (PRX1). Ca2+-binding to CRX is critical for its TRX activity and for efficient binding and reduction of PRX1. Thereby, CRX represents a new class of Ca2+-dependent ‘sensor-responder' proteins. Genetically engineered Chlamydomonas strains with strongly diminished amounts of CRX revealed altered photosynthetic electron transfer and were affected in oxidative stress response underpinning a function of CRX in stress acclimation. Calcium and redox signalling have important roles in acclimation processes. Here, the authors characterise a protein from Chlamydomonas reinhardtii that can integrate calcium and redox-related signalling.