3EA4

Arabidopsis thaliana acetohydroxyacid synthase in complex with monosulfuron-ester


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.200 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Crystal structures of two novel sulfonylurea herbicides in complex with Arabidopsis thaliana acetohydroxyacid synthase.

Wang, J.-G.Lee, P.K.Dong, Y.-H.Pang, S.S.Duggleby, R.G.Li, Z.-M.Guddat, L.W.

(2009) FEBS J 276: 1282-1290

  • DOI: https://doi.org/10.1111/j.1742-4658.2009.06863.x
  • Primary Citation of Related Structures:  
    3E9Y, 3EA4

  • PubMed Abstract: 

    Acetohydroxyacid synthase (AHAS; EC 2.2.1.6) is the first enzyme in the biosynthetic pathway of the branched-chain amino acids. It catalyzes the conversion of two molecules of pyruvate into 2-acetolactate or one molecule of pyruvate and one molecule of 2-ketobutyrate into 2-aceto-2-hydroxybutyrate. AHAS requires the cofactors thiamine diphosphate (ThDP), Mg(2+) and FAD for activity. The herbicides that target this enzyme are effective in protecting a broad range of crops from weed species. However, resistance in the field is now a serious problem worldwide. To address this, two new sulfonylureas, monosulfuron and monosulfuron ester, have been developed as commercial herbicides in China. These molecules differ from the traditional sulfonylureas in that the heterocyclic ring attached to the nitrogen atom of the sulfonylurea bridge is monosubstituted rather than disubstituted. The structures of these compounds in complex with the catalytic subunit of Arabidopsis thaliana AHAS have been determined to 3.0 and 2.8 A, respectively. In both complexes, these molecules are bound in the tunnel leading to the active site, such that the sole substituent of the heterocyclic ring is buried deepest and oriented towards the ThDP. Unlike the structures of Arabidopsis thaliana AHAS in complex with the classic disubstituted sulfonylureas, where ThDP is broken, this cofactor is intact and present most likely as the hydroxylethyl intermediate.


  • Organizational Affiliation

    State Key Laboratory of Elemento-Organic Chemistry, National Pesticide Engineering Research Center, Nankai University, Tianjin, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Acetolactate synthase, chloroplastic584Arabidopsis thalianaMutation(s): 0 
Gene Names: CSR 1.2At3g48560T8P19.70
EC: 2.2.1.6
UniProt
Find proteins for P17597 (Arabidopsis thaliana)
Explore P17597 
Go to UniProtKB:  P17597
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP17597
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
FAB
Query on FAB

Download Ideal Coordinates CCD File 
C [auth A]FLAVIN-ADENINE DINUCLEOTIDE-N5-ISOBUTYL KETONE
C31 H39 N9 O16 P2
VVZGWZAMSAFRNS-UYOVOMPXSA-N
TDM
Query on TDM

Download Ideal Coordinates CCD File 
E [auth A]2-[(2E)-3-[(4-AMINO-2-METHYLPYRIMIDIN-5-YL)METHYL]-2-(1-HYDROXYETHYLIDENE)-4-METHYL-2,3-DIHYDRO-1,3-THIAZOL-5-YL]ETHYL TRIHYDROGEN DIPHOSPHATE
C14 H22 N4 O8 P2 S
ZZLCKFKIIVXBQU-NTEUORMPSA-N
2SM
Query on 2SM

Download Ideal Coordinates CCD File 
B [auth A]methyl 2-{[(4-methylpyrimidin-2-yl)carbamoyl]sulfamoyl}benzoate
C14 H14 N4 O5 S
VGBNSONMEGTIDX-UHFFFAOYSA-N
NHE
Query on NHE

Download Ideal Coordinates CCD File 
D [auth A]2-[N-CYCLOHEXYLAMINO]ETHANE SULFONIC ACID
C8 H17 N O3 S
MKWKNSIESPFAQN-UHFFFAOYSA-N
MG
Query on MG

Download Ideal Coordinates CCD File 
F [auth A]MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
CSD
Query on CSD
A
L-PEPTIDE LINKINGC3 H7 N O4 SCYS
Binding Affinity Annotations 
IDSourceBinding Affinity
2SM BindingDB:  3EA4 Ki: min: 260, max: 8530 (nM) from 2 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.199 
  • R-Value Observed: 0.200 
  • Space Group: P 64 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 178.468α = 90
b = 178.468β = 90
c = 184.948γ = 120
Software Package:
Software NamePurpose
ADSCdata collection
CCP4model building
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
CCP4phasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-03-31
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2014-11-12
    Changes: Non-polymer description
  • Version 1.3: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.4: 2024-11-13
    Changes: Structure summary