3KB3: Crystal Structure Of Abscisic Acid-Bound Pyl2 In Complex With Hab1

Citation:
Abstract
Abscisic acid (ABA) is a ubiquitous hormone that regulates plant growth, development and responses to environmental stresses. Its action is mediated by the PYR/PYL/RCAR family of START proteins, but it remains unclear how these receptors bind ABA and, in turn, how hormone binding leads to inhibition of the downstream type 2C protein phosphatase (PP2C) effectors. Here we report crystal structures of apo and ABA-bound receptors as well as a ternary PYL2-ABA-PP2C complex. The apo receptors contain an open ligand-binding pocket flanked by a gate that closes in response to ABA by way of conformational changes in two highly conserved beta-loops that serve as a gate and latch. Moreover, ABA-induced closure of the gate creates a surface that enables the receptor to dock into and competitively inhibit the PP2C active site. A conserved tryptophan in the PP2C inserts directly between the gate and latch, which functions to further lock the receptor in a closed conformation. Together, our results identify a conserved gate-latch-lock mechanism underlying ABA signalling.
PDB ID: 3KB3Download
MMDB ID: 78640
PDB Deposition Date: 2009/10/20
Updated in MMDB: 2009/12
Experimental Method:
x-ray diffraction
Resolution: 1.95  Å
Source Organism:
Similar Structures:
Biological Unit for 3KB3: dimeric; determined by author and by software (PISA)
Molecular Components in 3KB3
Label Count Molecule
Proteins (2 molecules)
1
Putative Uncharacterized Protein At2g26040(Gene symbol: PYL2)
Molecule annotation
1
Protein Phosphatase 2C 16(Gene symbol: HAB1)
Molecule annotation
Chemicals (4 molecules)
1
1
2
3
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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