Functional mechanism of the abscisic acid agonist pyrabactin.

TitleFunctional mechanism of the abscisic acid agonist pyrabactin.
Publication TypeJournal Article
Year of Publication2010
AuthorsHao, Q, Yin, P, Yan, C, Yuan, X, Li, W, Zhang, Z, Liu, L, Wang, J, Yan, N
JournalJ Biol Chem
Volume285
Issue37
Pagination28946-52
Date Published2010 Sep 10
ISSN1083-351X
KeywordsAbscisic Acid, Arabidopsis, Arabidopsis Proteins, Binding Sites, Crystallography, X-Ray, Germination, Ligands, Naphthalenes, Seeds, Structure-Activity Relationship, Sulfonamides
Abstract

Pyrabactin is a synthetic abscisic acid (ABA) agonist that selectively inhibits seed germination. The use of pyrabactin was pivotal in the identification of the PYR1/PYL/RCAR family (PYL) of proteins as the ABA receptor. Although they both act through PYL proteins, pyrabactin and ABA share no apparent chemical or structural similarity. It remains unclear how pyrabactin functions as an ABA agonist. Here, we report the crystal structure of pyrabactin in complex with PYL1 at 2.4 A resolution. Structural and biochemical analyses revealed that recognition of pyrabactin by the pocket residues precedes the closure of switch loop CL2. Structural comparison between pyrabactin- and ABA-bound PYL1 reveals a general principle in the arrangements of function groups of the two distinct ligands. The study provides a framework for the development of novel ABA agonists that may have applicable potentials in agriculture.

DOI10.1074/jbc.M110.149005
Alternate JournalJ. Biol. Chem.
PubMed ID20554531
PubMed Central IDPMC2937921