Membranes as Structural Antioxidants: RECYCLING OF MALONDIALDEHYDE TO ITS SOURCE IN OXIDATION-SENSITIVE CHLOROPLAST FATTY ACIDS.

Détails

ID Serval
serval:BIB_75B744829AF6
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Membranes as Structural Antioxidants: RECYCLING OF MALONDIALDEHYDE TO ITS SOURCE IN OXIDATION-SENSITIVE CHLOROPLAST FATTY ACIDS.
Périodique
The Journal of biological chemistry
Auteur(s)
Schmid-Siegert E., Stepushenko O., Glauser G., Farmer E.E.
ISSN
1083-351X (Electronic)
ISSN-L
0021-9258
Statut éditorial
Publié
Date de publication
17/06/2016
Peer-reviewed
Oui
Volume
291
Numéro
25
Pages
13005-13013
Langue
anglais
Notes
Publication types: Journal Article ; Research Support, Non-U.S. Gov't
Publication Status: ppublish
Résumé
Genetic evidence suggests that membranes rich in polyunsaturated fatty acids (PUFAs) act as supramolecular antioxidants that capture reactive oxygen species, thereby limiting damage to proteins. This process generates lipid fragmentation products including malondialdehyde (MDA), an archetypal marker of PUFA oxidation. We observed transient increases in levels of endogenous MDA in wounded Arabidopsis thaliana leaves, raising the possibility that MDA is metabolized. We developed a rigorous ion exchange method to purify enzymatically generated (13)C- and (14)C-MDA. Delivered as a volatile to intact plants, MDA was efficiently incorporated into lipids. Mass spectral and genetic analyses identified the major chloroplast galactolipid: α-linolenic acid (18:3)-7Z,10Z,13Z-hexadecatrienoic acid (16:3)-monogalactosyldiacylglycerol (18:3-16:3-MGDG) as an end-product of MDA incorporation. Consistent with this, the fad3-2 fad7-2 fad8 mutant that lacks tri-unsaturated fatty acids incorporated (14)C-MDA into 18:2-16:2-MGDG. Saponification of (14)C-labeled 18:3-16:3-MGDG revealed 84% of (14)C-label in the acyl groups with the remaining 16% in the head group. 18:3-16:3-MGDG is enriched proximal to photosystem II and is likely a major in vivo source of MDA in photosynthetic tissues. We propose that nonenzymatically generated lipid fragments such as MDA are recycled back into plastidic galactolipids that, in their role as cell protectants, can again be fragmented into MDA.

Mots-clé
Acetates/metabolism, Antioxidants/metabolism, Arabidopsis/metabolism, Cell Membrane/metabolism, Chloroplasts/metabolism, Fatty Acids/metabolism, Lipid Metabolism, Malondialdehyde/metabolism, Membrane Lipids/physiology, Oxidation-Reduction, Oxidative Stress, Plant Leaves/metabolism
Pubmed
Open Access
Oui
Création de la notice
17/05/2016 18:46
Dernière modification de la notice
08/05/2019 20:31
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