7NB9

E. coli NfsA with nitrofurantoin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.09 Å
  • R-Value Free: 0.126 
  • R-Value Work: 0.104 
  • R-Value Observed: 0.105 

Starting Model: experimental
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Literature

The structures of E. coli NfsA bound to the antibiotic nitrofurantoin; to 1,4-benzoquinone and to FMN.

Day, M.A.Jarrom, D.Christofferson, A.J.Graziano, A.E.Anderson, J.L.R.Searle, P.F.Hyde, E.I.White, S.A.

(2021) Biochem J 478: 2601-2617

  • DOI: https://doi.org/10.1042/BCJ20210160
  • Primary Citation of Related Structures:  
    7NB9, 7NIY, 7NMP, 7NNX

  • PubMed Abstract: 

    NfsA is a dimeric flavoprotein that catalyses the reduction in nitroaromatics and quinones by NADPH. This reduction is required for the activity of nitrofuran antibiotics. The crystal structure of free Escherichia coli NfsA and several homologues have been determined previously, but there is no structure of the enzyme with ligands. We present here crystal structures of oxidised E. coli NfsA in the presence of several ligands, including the antibiotic nitrofurantoin. Nitrofurantoin binds with the furan ring, rather than the nitro group that is reduced, near the N5 of the FMN. Molecular dynamics simulations show that this orientation is only favourable in the oxidised enzyme, while potentiometry suggests that little semiquinone is formed in the free protein. This suggests that the reduction occurs by direct hydride transfer from FMNH- to nitrofurantoin bound in the reverse orientation to that in the crystal structure. We present a model of nitrofurantoin bound to reduced NfsA in a viable hydride transfer orientation. The substrate 1,4-benzoquinone and the product hydroquinone are positioned close to the FMN N5 in the respective crystal structures with NfsA, suitable for reaction, but are mobile within the active site. The structure with a second FMN, bound as a ligand, shows that a mobile loop in the free protein forms a phosphate-binding pocket. NfsA is specific for NADPH and a similar conformational change, forming a phosphate-binding pocket, is likely to also occur with the natural cofactor.


  • Organizational Affiliation

    School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Oxygen-insensitive NADPH nitroreductase240Escherichia coli K-12Mutation(s): 0 
Gene Names: nfsAmda18mdaAybjBb0851JW0835
EC: 1
UniProt
Find proteins for P17117 (Escherichia coli (strain K12))
Explore P17117 
Go to UniProtKB:  P17117
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP17117
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.09 Å
  • R-Value Free: 0.126 
  • R-Value Work: 0.104 
  • R-Value Observed: 0.105 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.396α = 90
b = 51.857β = 134.1
c = 64.583γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
PDB_EXTRACTdata extraction
MOSFLMdata reduction
pointlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2021-07-21
    Type: Initial release
  • Version 1.1: 2024-01-31
    Changes: Data collection, Database references, Refinement description