Enantiopyochelin outer membrane TonB-dependent transporter from Pseudomonas fluorescens bound to the ferri-enantiopyochelin

Experimental Data Snapshot

  • Resolution: 3.26 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 

Starting Model: experimental
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Pyochelin enantiomers and their outer-membrane siderophore transporters in fluorescent pseudomonads: structural bases for unique enantiospecific recognition

Brillet, K.Reimmann, C.Mislin, G.L.A.Noel, S.Rognan, D.Schalk, I.J.Cobessi, D.

(2011) J Am Chem Soc 133: 16503-16509

  • DOI: https://doi.org/10.1021/ja205504z
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Pyochelin (Pch) and enantiopyochelin (EPch) are enantiomeric siderophores, with three chiral centers, produced under iron limitation conditions by Pseudomonas aeruginosa and Pseudomonas fluorescens , respectively. After iron chelation in the extracellular medium, Pch-Fe and EPch-Fe are recognized and transported by their specific outer-membrane transporters: FptA in P. aeruginosa and FetA in P. fluorescens . Structural analysis of FetA-EPch-Fe and FptA-Pch-Fe, combined with mutagenesis and docking studies revealed the structural basis of the stereospecific recognition of these enantiomers by their respective transporters. Whereas FetA and FptA have a low sequence identity but high structural homology, the Pch and EPch binding pockets do not share any structural homology, but display similar physicochemical properties. The stereospecific recognition of both enantiomers by their corresponding transporters is imposed by the configuration of the siderophore's C4'' and C2'' chiral centers. This recognition involves specific hydrogen bonds between the Arg91 guanidinium group and EPch-Fe for FetA and between the Leu117-Leu116 main chain and Pch-Fe for FptA. FetA and FptA are the first membrane receptors to be structurally described with opposite binding enantioselectivities for their ligands, giving insights into the structural basis of their enantiospecificity.

  • Organizational Affiliation

    UMR 7242 Biotechnologie et Signalisation Cellulaire, Université de Strasbourg-CNRS, Irebs-ESBS, Boulevard Sébastien Brant, 67412 Illkirch, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Enantio-pyochelin receptor
A, B
748Pseudomonas fluorescensMutation(s): 0 
Gene Names: fetA
Membrane Entity: Yes 
Find proteins for C5I2D9 (Pseudomonas fluorescens)
Explore C5I2D9 
Go to UniProtKB:  C5I2D9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC5I2D9
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.26 Å
  • R-Value Free: 0.259 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.216 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 155.07α = 90
b = 170.83β = 90
c = 232.62γ = 90
Software Package:
Software NamePurpose
X-NEMOdata collection
XDSdata reduction
XDSdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-12-07
    Type: Initial release
  • Version 1.1: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description