X-ray Crystallographic Structure of a Pseudomonas aeruginosa Azoreductase in Complex with Methyl Red.

Experimental Data Snapshot

  • Resolution: 2.18 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.194 

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Molecular Cloning, Characterisation and Ligand- Bound Structure of an Azoreductase from Pseudomonas Aeruginosa

Wang, C.-J.Hagemeier, C.Rahman, N.Lowe, E.D.Noble, M.E.M.Coughtrie, M.Sim, E.Westwood, I.M.

(2007) J Mol Biol 373: 1213

  • DOI: https://doi.org/10.1016/j.jmb.2007.08.048
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The gene PA0785 from Pseudomonas aeruginosa strain PAO1, which is annotated as a probable acyl carrier protein phosphodiesterase (acpD), has been cloned and heterologously overexpressed in Escherichia coli. The purified recombinant enzyme exhibits activity corresponding to that of azoreductase but not acpD. Each recombinant protein molecule has an estimated molecular mass of 23,050 Da and one non-covalently bound FMN as co-factor. This enzyme, now identified as azoreductase 1 from Pseudomonas aeruginosa (paAzoR1), is a flavodoxin-like protein with an apparent molecular mass of 110 kDa as determined by gel-filtration chromatography, indicating that the protein is likely to be tetrameric in solution. The three-dimensional structure of paAzoR1, in complex with the substrate methyl red, was solved at a resolution of 2.18 A by X-ray crystallography. The protein exists as a dimer of dimers in the crystal lattice, with two spatially separated active sites per dimer, and the active site of paAzoR1 was shown to be a well-conserved hydrophobic pocket formed between two monomers. The paAzoR1 enzyme is able to reduce different classes of azo dyes and activate several azo pro-drugs used in the treatment of inflammatory bowel disease (IBD). During azo reduction, FMN serves as a redox centre in the electron-transferring system by mediating the electron transfer from NAD(P)H to the azo substrate. The spectral properties of paAzoR1 demonstrate the hydrophobic interaction between FMN and the active site in the protein. The structure of the ligand-bound protein also highlights the pi-stacking interactions between FMN and the azo substrate.

  • Organizational Affiliation

    Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
215Pseudomonas aeruginosa PAO1Mutation(s): 0 
Find proteins for Q9I5F3 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Explore Q9I5F3 
Go to UniProtKB:  Q9I5F3
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9I5F3
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.18 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.194 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 82.55α = 90
b = 82.55β = 90
c = 108.65γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-11-13
    Type: Initial release
  • Version 1.1: 2011-06-23
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description