Protection against photooxidative injury of tobacco leaves by 2-alkenal reductase.: Detoxication of lipid peroxide-derived reactive carbonyls
Protection against photooxidative injury of tobacco leaves by 2-alkenal reductase.: Detoxication of lipid peroxide-derived reactive carbonyls
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DOI：
10.1104/pp.105.070391
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发表时间：
2005-12-01
期刊：
影响因子：
7.4
通讯作者：
Kushnir, S
中科院分区：
文献类型：
--
作者：
Mano, J;Belles-Boix, E;Kushnir, S
脂质过氧化物的降解导致形成细胞毒性2-烯醛和氧杂环己烯（统称为反应性羰基）。来自拟南芥（Arabidopsis thaliana）的新的NADPH依赖性氧化还原酶2-烯醛还原酶（AER; EC www.example.com），其由基因At5g16970编码，催化活性羰基的α，β-不饱和键的还原，因此推测其在植物的抗氧化防御中起作用。在这里，我们表明，拟南芥AER（At-AER）具有广泛的底物谱生物相关的活性羰基。除了2-烯醛外，该酶还识别脂质过氧化物衍生的氧烯9-氧代-十八碳-（10 E），（12 Z）-二烯酸和13-氧代-十八碳-（9 E），（11 Z）-二烯酸以及有效的遗传毒素4-氧代-（2 E）-壬烯醛作为底物，这表明AER在活性羰基的解毒中具有关键作用。为了通过体内研究验证这一结论，产生了AER活性水平比对照植物高100至250倍的转基因烟草（Nicotiana tabacum）植物。工程化植物表现出明显更少的损伤，无论是（1）外源给予4-羟基-（2E）-壬烯醛，（2）甲基紫精加光处理，或（3）强光。我们进一步表明，At-AER蛋白融合的Aequorea维多利亚绿色荧光蛋白定位在胞浆和细胞核中的黄色2细胞。这些结果表明，活性羰基介导叶细胞中的光氧化损伤，和在胞质溶胶中的At-AER保护细胞通过减少光产生的活性羰基的α，β-不饱和键。
Degradation of lipid peroxides leads to the formation of cytotoxic 2-alkenals and oxenes (collectively designated reactive carbonyls). The novel NADPH-dependent oxidoreductase 2-alkenal reductase (AER; EC 1.3.1.74) from Arabidopsis (Arabidopsis thaliana), which is encoded by the gene At5g16970, catalyzes the reduction of the alpha,beta-unsaturated bond of reactive carbonyls, and hence is presumed to function in antioxidative defense in plants. Here we show that Arabidopsis AER (At-AER) has a broad substrate spectrum to biologically relevant reactive carbonyls. Besides 2-alkenals, the enzyme recognized as substrates the lipid peroxide-derived oxenes 9-oxo-octadeca-(10E),(12Z)-dienoic acid and 13-oxo-octadeca-(9E),(11Z)-dienoic acid, as well as the potent genotoxin 4-oxo-(2E)-nonenal, altogether suggesting AER has a key role in the detoxification of reactive carbonyls. To validate this conclusion by in vivo studies, transgenic tobacco ( Nicotiana tabacum) plants that had 100- to 250-fold higher AER activity levels than control plants were generated. The engineered plants exhibited significantly less damage from either (1) the exogenously administered 4-hydroxy-(2E)-nonenal, (2) treatment with methyl viologen plus light, or (3) intense light. We further show that the At-AER protein fused with the Aequorea victoria green fluorescent protein localizes in cytosol and the nucleus in Bright-Yellow 2 cells. These results indicate that reactive carbonyls mediate photooxidative injury in leaf cells, and At-AER in the cytosol protects the cells by reducing the alpha,beta-unsaturated bond of the photoproduced reactive carbonyls.