5TWB

Oxidoreductase IruO in the reduced form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.822 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Iron Uptake Oxidoreductase (IruO) Uses a Flavin Adenine Dinucleotide Semiquinone Intermediate for Iron-Siderophore Reduction.

Kobylarz, M.J.Heieis, G.A.Loutet, S.A.Murphy, M.E.P.

(2017) ACS Chem. Biol. 12: 1778-1786

  • DOI: 10.1021/acschembio.7b00203
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Many pathogenic bacteria including Staphylococcus aureus use iron-chelating siderophores to acquire iron. Iron uptake oxidoreductase (IruO), a flavin adenine dinucleotide (FAD)-containing nicotinamide adenine dinucleotide phosphate (NADPH)-dependent ...

    Many pathogenic bacteria including Staphylococcus aureus use iron-chelating siderophores to acquire iron. Iron uptake oxidoreductase (IruO), a flavin adenine dinucleotide (FAD)-containing nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reductase from S. aureus, functions as a reductase for IsdG and IsdI, two paralogous heme degrading enzymes. Also, the gene encoding for IruO was shown to be required for growth of S. aureus on hydroxamate siderophores as a sole iron source. Here, we show that IruO binds the hydroxamate-type siderophores desferrioxamine B and ferrichrome A with low micromolar affinity and in the presence of NADPH, Fe(II) was released. Steady-state kinetics of Fe(II) release provides k cat /K m values in the range of 600 to 7000 M -1 s -1 for these siderophores supporting a role for IruO as a siderophore reductase in iron utilization. Crystal structures of IruO were solved in two distinct conformational states mediated by the formation of an intramolecular disulfide bond. A putative siderophore binding site was identified adjacent to the FAD cofactor. This site is partly occluded in the oxidized IruO structure consistent with this form being less active than reduced IruO. This reduction in activity could have a physiological role to limit iron release under oxidative stress conditions. Visible spectroscopy of anaerobically reduced IruO showed that the reaction proceeds by a single electron transfer mechanism through an FAD semiquinone intermediate. From the data, a model for single electron siderophore reduction by IruO using NADPH is described.


    Organizational Affiliation

    The Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia , Vancouver, British Columbia V6T 1Z3; Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ferredoxin--NADP reductase
A
344Staphylococcus aureus (strain USA300)Mutation(s): 0 
EC: 1.18.1.2
Find proteins for Q2FEC4 (Staphylococcus aureus (strain USA300))
Go to UniProtKB:  Q2FEC4
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
FAD
Query on FAD

Download SDF File 
Download CCD File 
A
FLAVIN-ADENINE DINUCLEOTIDE
C27 H33 N9 O15 P2
VWWQXMAJTJZDQX-UYBVJOGSSA-N
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.822 Å
  • R-Value Free: 0.227 
  • R-Value Work: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 157.170α = 90.00
b = 43.600β = 93.44
c = 51.240γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
MOSFLMdata reduction
PHENIXphasing
SCALAdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Canadian Institutes of Health ResearchCanadaMOP-102596

Revision History 

  • Version 1.0: 2017-10-04
    Type: Initial release