7PLE

ArsH of Paracoccus denitrificans


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.255 
  • R-Value Observed: 0.315 

Starting Model: other
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This is version 1.3 of the entry. See complete history


Literature

The ArsH Protein Product of the Paracoccus denitrificans ars Operon Has an Activity of Organoarsenic Reductase and Is Regulated by a Redox-Responsive Repressor.

Sedlacek, V.Kryl, M.Kucera, I.

(2022) Antioxidants (Basel) 11

  • DOI: https://doi.org/10.3390/antiox11050902
  • Primary Citation of Related Structures:  
    7PLE

  • PubMed Abstract: 

    Paracoccus denitrificans ArsH is encoded by two identical genes located in two distinct putative arsenic resistance ( ars ) operons. Escherichia coli -produced recombinant N-His 6 -ArsH was characterized both structurally and kinetically. The X-ray structure of ArsH revealed a flavodoxin-like domain and motifs for the binding of flavin mononucleotide (FMN) and reduced nicotinamide adenine dinucleotide phosphate (NADPH). The protein catalyzed FMN reduction by NADPH via ternary complex mechanism. At a fixed saturating FMN concentration, it acted as an NADPH-dependent organoarsenic reductase displaying ping-pong kinetics. A 1:1 enzymatic reaction of phenylarsonic acid with the reduced form of FMN (FMNH 2 ) and formation of phenylarsonous acid were observed. Growth experiments with P. denitrificans and E. coli revealed increased toxicity of phenylarsonic acid to cells expressing arsH , which may be related to in vivo conversion of pentavalent As to more toxic trivalent form. ArsH expression was upregulated not only by arsenite, but also by redox-active agents paraquat, tert-butyl hydroperoxide and diamide. A crucial role is played by the homodimeric transcriptional repressor ArsR, which was shown in in vitro experiments to monomerize and release from the DNA-target site. Collectively, our results establish ArsH as responsible for enhancement of organo-As(V) toxicity and demonstrate redox control of ars operon.


  • Organizational Affiliation

    Department of Biochemistry, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
NADPH-dependent FMN reductase
A, B, C, D
271Paracoccus denitrificans PD1222Mutation(s): 0 
Gene Names: Pden_3133Pden_3339
UniProt
Find proteins for A1B6S0 (Paracoccus denitrificans (strain Pd 1222))
Explore A1B6S0 
Go to UniProtKB:  A1B6S0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA1B6S0
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.60 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.255 
  • R-Value Observed: 0.315 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 112.95α = 90
b = 112.95β = 90
c = 204.41γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
iMOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data

  • Released Date: 2021-10-27 
  • Deposition Author(s): Kryl, M.

Funding OrganizationLocationGrant Number
Czech Science FoundationCzech Republic16-18476S

Revision History  (Full details and data files)

  • Version 1.0: 2021-10-27
    Type: Initial release
  • Version 1.1: 2022-05-25
    Changes: Database references, Refinement description
  • Version 1.2: 2022-06-08
    Changes: Database references
  • Version 1.3: 2024-05-01
    Changes: Data collection, Refinement description