| Autor: |
Mano J; Science Research Center , Yamaguchi University, Yoshida 1677-1, Yamaguchi 753-8515, Japan. mano@yamaguchi-u.ac.jp, Belles-Boix E, Babiychuk E, Inzé D, Torii Y, Hiraoka E, Takimoto K, Slooten L, Asada K, Kushnir S |
| Jazyk: |
angličtina |
| Zdroj: |
Plant physiology [Plant Physiol] 2005 Dec; Vol. 139 (4), pp. 1773-83. Date of Electronic Publication: 2005 Nov 18. |
| DOI: |
10.1104/pp.105.070391 |
| Abstrakt: |
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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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