Abstract
Hormone-triggered activation of the jasmonate signaling pathway in Arabidopsis thaliana requires SCF(COI1)-mediated proteasome degradation of JAZ repressors. (-)-JA-L-Ile is the proposed bioactive hormone, and SCF(COI1) 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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Arabidopsis / metabolism*
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Chromatography, High Pressure Liquid
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Cyclopentanes / metabolism*
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Esterification
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Isoleucine / analogs & derivatives*
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Isoleucine / metabolism
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Signal Transduction
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Two-Hybrid System Techniques
Substances
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Cyclopentanes
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jasmonoyl-isoleucine
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Isoleucine
Associated data
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PubChem-Substance/57299395
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PubChem-Substance/57299396
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PubChem-Substance/57299397
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PubChem-Substance/57299398
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PubChem-Substance/57299399
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PubChem-Substance/57299400
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PubChem-Substance/57299401
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PubChem-Substance/57299402
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PubChem-Substance/57299403
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PubChem-Substance/57299404
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PubChem-Substance/57299405
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PubChem-Substance/57299406
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PubChem-Substance/57299407
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PubChem-Substance/57299408
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PubChem-Substance/57299409
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PubChem-Substance/57299410
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PubChem-Substance/57299411
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PubChem-Substance/57299412
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PubChem-Substance/57299413
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PubChem-Substance/57299414
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PubChem-Substance/57299415
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PubChem-Substance/57299416
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PubChem-Substance/57299417
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PubChem-Substance/57299418
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PubChem-Substance/57299419
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PubChem-Substance/57299420
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PubChem-Substance/57299421
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PubChem-Substance/57299422
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PubChem-Substance/57299423
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PubChem-Substance/57299424
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PubChem-Substance/57299425
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PubChem-Substance/57299426
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PubChem-Substance/57299427
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PubChem-Substance/57299428
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PubChem-Substance/57299429
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PubChem-Substance/57299430
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PubChem-Substance/57299431
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PubChem-Substance/57299432
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PubChem-Substance/57299433
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PubChem-Substance/57299434