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- Title
(+)-7-iso-Jasmonoyl-L-isoleucine is the endogenous bioactive jasmonate.
- Authors
Fonseca, Sandra; Chini, Andrea; Hamberg, Mats; Adie, Bruce; Porzel, Andrea; Kramell, Robert; Miersch, Otto; Wasternack, Claus; Solano, Roberto
- Abstract
Hormone-triggered activation of the jasmonate signaling pathway in Arabidopsis thaliana requires SCFCOI1-mediated proteasome degradation of JAZ repressors. (−)-JA-L-Ile is the proposed bioactive hormone, and SCFCOI1 is its likely receptor. We found that the biological activity of (−)-JA-L-Ile is unexpectedly low compared to coronatine and the synthetic isomer (+)-JA-L-Ile, which suggests that the stereochemical orientation of the cyclopentanone-ring side chains greatly affects receptor binding. Detailed GC-MS and HPLC analyses showed that the (−)-JA-L-Ile preparations currently used in ligand binding studies contain small amounts of the C7 epimer (+)-7-iso-JA-L-Ile. Purification of each of these molecules demonstrated that pure (−)-JA-L-Ile is inactive and that the active hormone is (+)-7-iso-JA-L-Ile, which is also structurally more similar to coronatine. In addition, we show that pH changes promote conversion of (+)-7-iso-JA-L-Ile to the inactive (−)-JA-L-Ile form, thus providing a simple mechanism that can regulate hormone activity through epimerization.
- Subjects
PLANT hormones; ARABIDOPSIS; BRASSICACEAE; LIGAND binding (Biochemistry); MOLECULES
- Publication
Nature Chemical Biology, 2009, Vol 5, Issue 5, p344
- ISSN
1552-4450
- Publication type
Article
- DOI
10.1038/nchembio.161