A GDSL Esterase/Lipase Catalyzes the Esterification of Lutein in Bread Wheat
| Autor: | Robert T. Furbank, Heather E. McFarlane, Kenneth J. Chalmers, Maria Ermakova, Kai Xun Chan, Daryl J. Mares, Ming Li, Jacinta L. Watkins, Diane E. Mather, Peter Sharp, Barry J. Pogson, Chongmei Dong, Ryan P. McQuinn |
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| Rok vydání: | 2019 |
| Předmět: |
0106 biological sciences
0301 basic medicine Lutein CAROTENOID BIOSYNTHESIS TURGIDUM CONY. DURUM Plant Science Biology 01 natural sciences Esterase LIPASE-LIKE PROTEIN 03 medical and health sciences chemistry.chemical_compound Lipase Carotenoid Research Articles Triticum 2. Zero hunger chemistry.chemical_classification FATTY-ACID Esterification Esterases Biology and Life Sciences food and beverages Bread Cell Biology ARABIDOPSIS Genetically modified rice Zeaxanthin ENDOSPERM LUTEIN 030104 developmental biology chemistry Biochemistry ESCHERICHIA-COLI Xanthophyll Acyltransferase biology.protein ANTIOXIDANT ACTIVITY THIOESTERASE-I STORAGE 010606 plant biology & botany |
| Zdroj: | Plant Cell PLANT CELL |
| ISSN: | 1532-298X 1040-4651 |
| Popis: | Xanthophylls are a class of carotenoids that are important micronutrients for humans. They are often found esterified with fatty acids in fruits, vegetables, and certain grains, including bread wheat (Triticum aestivum). Esterification promotes the sequestration and accumulation of carotenoids, thereby enhancing stability, particularly in tissues such as in harvested wheat grain. Here, we report on a plant xanthophyll acyltransferase (XAT) that is both necessary and sufficient for xanthophyll esterification in bread wheat grain. XAT contains a canonical Gly-Asp-Ser-Leu (GDSL) motif and is encoded by a member of the GDSL esterase/lipase gene family. Genetic evidence from allelic variants of wheat and transgenic rice (Oryza sativa) calli demonstrated that XAT catalyzes the formation of xanthophyll esters. XAT has broad substrate specificity and can esterify lutein, β-cryptoxanthin, and zeaxanthin using multiple acyl donors, yet it has a preference for triacylglycerides, indicating that the enzyme acts via transesterification. A conserved amino acid, Ser-37, is required for activity. Despite xanthophylls being synthesized in plastids, XAT accumulated in the apoplast. Based on analysis of substrate preferences and xanthophyll ester formation in vitro and in vivo using xanthophyll-accumulating rice callus, we propose that disintegration of the cellular structure during wheat grain desiccation facilitates access to lutein-promoting transesterification.plantcell;31/12/3092/FX1F1fx1. |
| Databáze: | OpenAIRE |
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