Single amino acid alteration between valine and isoleucine determines the distinct pyrabactin selectivity by PYL1 and PYL2.

TitleSingle amino acid alteration between valine and isoleucine determines the distinct pyrabactin selectivity by PYL1 and PYL2.
Publication TypeJournal Article
Year of Publication2010
AuthorsYuan, X, Yin, P, Hao, Q, Yan, C, Wang, J, Yan, N
JournalJ Biol Chem
Volume285
Issue37
Pagination28953-8
Date Published2010 Sep 10
ISSN1083-351X
KeywordsAbscisic Acid, Arabidopsis, Arabidopsis Proteins, Crystallography, X-Ray, Isoleucine, Protein Structure, Tertiary, Receptors, Cell Surface, Valine
Abstract

Abscisic acid (ABA) is one of the most important phytohormones in plant. PYL proteins were identified to be ABA receptors in Arabidopsis thaliana. Despite the remarkably high degree of sequence similarity, PYL1 and PYL2 exhibit distinct responses toward pyrabactin, an ABA agonist. PYL1 inhibits protein phosphatase type 2C upon binding of pyrabactin. In contrast, PYL2 appears relatively insensitive to this compound. The crystal structure of pyrabactin-bound PYL1 revealed that most of the PYL1 residues involved in pyrabactin binding are conserved, hence failing to explain the selectivity of pyrabactin for PYL1 over PYL2. To understand the molecular basis of pyrabactin selectivity, we determined the crystal structure of PYL2 in complex with pyrabactin at 1.64 A resolution. Structural comparison and biochemical analyses demonstrated that one single amino acid alteration between a corresponding valine and isoleucine determines the distinct pyrabactin selectivity by PYL1 and PYL2. These characterizations provide an important clue to dissecting the redundancy of PYL proteins.

DOI10.1074/jbc.M110.160192
Alternate JournalJ. Biol. Chem.
PubMed ID20630864
PubMed Central IDPMC2937922