2P1Q

Mechanism of Auxin Perception by the TIR1 ubiquitin ligase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Mechanism of auxin perception by the TIR1 ubiquitin ligase.

Tan, X.Calderon-Villalobos, L.I.Sharon, M.Zheng, C.Robinson, C.V.Estelle, M.Zheng, N.

(2007) Nature 446: 640-645

  • DOI: 10.1038/nature05731
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-lig ...

    Auxin is a pivotal plant hormone that controls many aspects of plant growth and development. Perceived by a small family of F-box proteins including transport inhibitor response 1 (TIR1), auxin regulates gene expression by promoting SCF ubiquitin-ligase-catalysed degradation of the Aux/IAA transcription repressors, but how the TIR1 F-box protein senses and becomes activated by auxin remains unclear. Here we present the crystal structures of the Arabidopsis TIR1-ASK1 complex, free and in complexes with three different auxin compounds and an Aux/IAA substrate peptide. These structures show that the leucine-rich repeat domain of TIR1 contains an unexpected inositol hexakisphosphate co-factor and recognizes auxin and the Aux/IAA polypeptide substrate through a single surface pocket. Anchored to the base of the TIR1 pocket, auxin binds to a partially promiscuous site, which can also accommodate various auxin analogues. Docked on top of auxin, the Aux/IAA substrate peptide occupies the rest of the TIR1 pocket and completely encloses the hormone-binding site. By filling in a hydrophobic cavity at the protein interface, auxin enhances the TIR1-substrate interactions by acting as a 'molecular glue'. Our results establish the first structural model of a plant hormone receptor.


    Organizational Affiliation

    Department of Pharmacology, University of Washington, School of Medicine, Box 357280, Seattle, Washington 98195, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SKP1-like protein 1A
A
160Arabidopsis thalianaMutation(s): 0 
Gene Names: SKP1A (ASK1, SKP1, UIP1)
Find proteins for Q39255 (Arabidopsis thaliana)
Go to UniProtKB:  Q39255
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
TRANSPORT INHIBITOR RESPONSE 1 protein
B
594Arabidopsis thalianaMutation(s): 0 
Gene Names: TIR1 (FBL1, WEI1)
Find proteins for Q570C0 (Arabidopsis thaliana)
Go to UniProtKB:  Q570C0
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Auxin-responsive protein IAA7
C
13Arabidopsis thalianaMutation(s): 0 
Gene Names: IAA7 (AXR2)
Find proteins for Q38825 (Arabidopsis thaliana)
Go to UniProtKB:  Q38825
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
IAC
Query on IAC

Download SDF File 
Download CCD File 
B
1H-INDOL-3-YLACETIC ACID
INDOLE ACETIC ACID
C10 H9 N O2
SEOVTRFCIGRIMH-UHFFFAOYSA-N
 Ligand Interaction
IHP
Query on IHP

Download SDF File 
Download CCD File 
B
INOSITOL HEXAKISPHOSPHATE
C6 H18 O24 P6
IMQLKJBTEOYOSI-GPIVLXJGSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.91 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.172 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 101.207α = 90.00
b = 82.472β = 104.05
c = 125.053γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
PHASERphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-04-10
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance