1YBH

Crystal structure of Arabidopsis thaliana Acetohydroxyacid synthase In Complex With A Sulfonylurea Herbicide Chlorimuron Ethyl


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.192 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Herbicide-binding sites revealed in the structure of plant acetohydroxyacid synthase

McCourt, J.A.Pang, S.S.King-Scott, J.Guddat, L.W.Duggleby, R.G.

(2006) Proc.Natl.Acad.Sci.Usa 103: 569-573

  • DOI: 10.1073/pnas.0508701103
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The sulfonylureas and imidazolinones are potent commercial herbicide families. They are among the most popular choices for farmers worldwide, because they are nontoxic to animals and highly selective. These herbicides inhibit branched-chain amino aci ...

    The sulfonylureas and imidazolinones are potent commercial herbicide families. They are among the most popular choices for farmers worldwide, because they are nontoxic to animals and highly selective. These herbicides inhibit branched-chain amino acid biosynthesis in plants by targeting acetohydroxyacid synthase (AHAS, EC 2.2.1.6). This report describes the 3D structure of Arabidopsis thaliana AHAS in complex with five sulfonylureas (to 2.5 A resolution) and with the imidazolinone, imazaquin (IQ; 2.8 A). Neither class of molecule has a structure that mimics the substrates for the enzyme, but both inhibit by blocking a channel through which access to the active site is gained. The sulfonylureas approach within 5 A of the catalytic center, which is the C2 atom of the cofactor thiamin diphosphate, whereas IQ is at least 7 A from this atom. Ten of the amino acid residues that bind the sulfonylureas also bind IQ. Six additional residues interact only with the sulfonylureas, whereas there are two residues that bind IQ but not the sulfonylureas. Thus, the two classes of inhibitor occupy partially overlapping sites but adopt different modes of binding. The increasing emergence of resistant weeds due to the appearance of mutations that interfere with the inhibition of AHAS is now a worldwide problem. The structures described here provide a rational molecular basis for understanding these mutations, thus allowing more sophisticated AHAS inhibitors to be developed. There is no previously described structure for any plant protein in complex with a commercial herbicide.


    Organizational Affiliation

    School of Molecular and Microbial Sciences, University of Queensland, Brisbane QLD 4072, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Acetolactate synthase, chloroplast
A
590Arabidopsis thalianaGene Names: ALS (AHAS, CSR1, TZP5)
EC: 2.2.1.6
Find proteins for P17597 (Arabidopsis thaliana)
Go to UniProtKB:  P17597
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FAD
Query on FAD

Download SDF File 
Download CCD File 
A
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
NHE
Query on NHE

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Download CCD File 
A
2-[N-CYCLOHEXYLAMINO]ETHANE SULFONIC ACID
N-CYCLOHEXYLTAURINE; CHES
C8 H17 N O3 S
MKWKNSIESPFAQN-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

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Download CCD File 
A
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
CIE
Query on CIE

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Download CCD File 
A
2-[[[[(4-CHLORO-6-METHOXY-2-PYRIMIDINYL)AMINO]CARBONYL]AMINO]SULFONYL]BENZOIC ACID ETHYL ESTER
CHLORIMURON ETHYL
C15 H15 Cl N4 O6 S
NSWAMPCUPHPTTC-UHFFFAOYSA-N
 Ligand Interaction
P22
Query on P22

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Download CCD File 
A
ETHYL DIHYDROGEN DIPHOSPHATE
C2 H8 O7 P2
OJDJHGIXNZPZFD-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CSD
Query on CSD
A
L-PEPTIDE LINKINGC3 H7 N O4 SCYS
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
CIEKi: 8 nM (99) BINDINGDB
CIEKi: 10.8 nM BINDINGMOAD
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.223 
  • R-Value Work: 0.192 
  • Space Group: P 64 2 2
Unit Cell:
Length (Å)Angle (°)
a = 178.518α = 90.00
b = 178.518β = 90.00
c = 184.776γ = 120.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
DENZOdata reduction
CNSrefinement
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-01-10
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance