Identification of genes coding for functional zeaxanthin epoxidases in the diatom Phaeodactylum tricornutum
| Autor: | Claudia Büchel, Ulrike Eilers, Lars Dietzel, Jürgen Breitenbach, Gerhard Sandmann |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Lutein Physiology Zeaxanthin epoxidase Arabidopsis Plant Science Xanthophylls Mixed Function Oxygenases 03 medical and health sciences chemistry.chemical_compound Zeaxanthins Fucoxanthin Arabidopsis thaliana Phaeodactylum tricornutum Diatoms chemistry.chemical_classification biology Genetic Complementation Test food and beverages biology.organism_classification Carotenoids eye diseases Complementation Zeaxanthin Kinetics 030104 developmental biology chemistry Biochemistry Xanthophyll Mutation biology.protein Oxidoreductases Agronomy and Crop Science |
| Zdroj: | Journal of Plant Physiology. 192:64-70 |
| ISSN: | 0176-1617 |
| DOI: | 10.1016/j.jplph.2016.01.006 |
| Popis: | Phaeodactylum tricornutum like other diatoms synthesizes fucoxanthin and diadinoxanthin as major carotenoid end products. The genes involved have recently been assigned for early pathway steps. Beyond β-carotene, only gene candidates for β-carotene hydroxylase, zeaxanthin epoxidase and zeaxanthin de-epoxidase have been proposed from the available genome sequence. The two latter enzymes may be involved in the two different xanthophyll cycles which operate in P. tricornutum. The function of three putative zeaxanthin epoxidase genes (zep) was addressed by pathway complementation in the Arabidopsis thaliana Zep mutant npq2. Genes zep2 and zep3 were able to restore zeaxanthin epoxidation and a functional xanthophyll cycle but the corresponding enzymes exhibited different catalytic activities. Zep3 functioned as a zeaxanthin epoxidase whereas Zep2 exhibited a broader substrate specificity additionally converting lutein to lutein-5,6-epoxide. Although zep1 was transcribed and the protein could be identified after import into the chloroplast in A. thaliana, Zep1 was found not to be functional in zeaxanthin epoxidation. The non-photochemical quenching kinetics of wild type A. thaliana was only restored in transformant npq2-zep3. |
| Databáze: | OpenAIRE |
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