Structure of fe2-HPPD bound to NTBC

Experimental Data Snapshot

  • Resolution: 2.50 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 

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Structure of the Ferrous Form of (4-Hydroxyphenyl)pyruvate Dioxygenase from Streptomyces avermitilis in Complex with the Therapeutic Herbicide, NTBC

Brownlee, J.Johnson-Winters, K.Harrison, D.H.T.Moran, G.R.

(2004) Biochemistry 43: 6370-6377

  • DOI: https://doi.org/10.1021/bi049317s
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Di- and triketone inhibitors of (4-hydroxyphenyl)pyruvate dioxygenase (HPPD) are both effective herbicides and therapeutics. The inhibitory activity is used to halt the production of lipophilic redox cofactors in plants and also in humans to prevent accumulation of toxic metabolic byproducts that arise from specific inborn defects of tyrosine catabolism. The three-dimensional structure of the Fe(II) form of HPPD from Streptomyces avermitilis in complex with the inhibitor 2-[2-nitro-4-(triflouromethyl)benzoyl]-1,3-cyclohexanedione (NTBC) has been determined at a resolution of 2.5 A. NTBC coordinates to the active site metal ion, located at the bottom of a wide solvent-accessible cavity in the C-terminal domain of the protein. The iron is liganded in a predominantly five-coordinate, distorted square-pyramidal arrangement in which Glu349, His187, and His270 are protein-derived ligands and two other ligands are from the 5' and 7' oxygens of NTBC. There is a low-occupancy water molecule in the sixth coordination site in one of the protomers. The distance to His270 is unusually long at 2.5 A, and its orientation is somewhat distorted from ideal ligand geometry to within 2.8 A of the inhibitor nitro group. In contrast to the tetrameric quartenary structure observed for HPPD from other bacterial sources, the asymmetric unit is composed of two weakly associated protomers with a buried surface area of 1266 A(2) and a total of 12 hydrogen-bonding and no electrostatic interactions. The overall tertiary structure is similar to that of HPPD from Pseudomonas fluorescens (Serre et al., (1999) Structure 7, 977-988), although the position of the C-terminal alpha-helix is dramatically shifted. This C-terminal alpha-helix provides Phe364, which in combination with Phe336 sandwiches the phenyl ring of the bound NTBC; no other significant hydrogen-bonding or charge-pairing interactions are observed. Moreover, the structure reveals that, with the exception of Val189, NTBC makes contacts to only fully conserved amino acids. The combination of bidentate metal-ion coordination and pi-stacked aromatic rings is suggestive of a binding mode for the substrate and/or a transition state, which may be the origin of the exceedingly high affinity these inhibitors have for HPPD.

  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, Illinois 60064, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
4-hydroxyphenylpyruvate dioxygenase
A, B
381Streptomyces avermitilisMutation(s): 0 
Gene Names: HPDSAV5149
Find proteins for Q53586 (Streptomyces avermitilis (strain ATCC 31267 / DSM 46492 / JCM 5070 / NBRC 14893 / NCIMB 12804 / NRRL 8165 / MA-4680))
Explore Q53586 
Go to UniProtKB:  Q53586
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ53586
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.50 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.288α = 90
b = 162.045β = 90
c = 56.15γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-06-15
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-02-14
    Changes: Data collection, Database references, Derived calculations