2CN4

The crystal structure of the secreted dimeric form of the hemophore HasA reveals a domain swapping with an exchanged heme ligand


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.169 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The Crystal Structure of the Secreted Dimeric Form of the Hemophore Hasa Reveals a Domain Swapping with an Exchanged Heme Ligand

Czjzek, M.Letoffe, S.Wandersman, C.Delepierre, M.Lecroisey, A.Izadi-Pruneyre, N.

(2007) J.Mol.Biol. 365: 1176

  • DOI: 10.1016/j.jmb.2006.10.063

  • PubMed Abstract: 
  • To satisfy their iron needs, several Gram-negative bacteria use a heme uptake system involving an extracellular heme-binding protein called hemophore. The function of the hemophore is to acquire free or hemoprotein-bound heme and to transfer it to Ha ...

    To satisfy their iron needs, several Gram-negative bacteria use a heme uptake system involving an extracellular heme-binding protein called hemophore. The function of the hemophore is to acquire free or hemoprotein-bound heme and to transfer it to HasR, its specific outer membrane receptor, by protein-protein interaction. The hemophore HasA secreted by Serratia marcescens, an opportunistic pathogen, was the first to be identified and is now very well characterized. HasA is a monomer that binds one b heme with strong affinity. The heme in HasA is highly exposed to solvent and coordinated by an unusual pair of ligands, a histidine and a tyrosine. Here, we report the identification, the characterization and the X-ray structure of a dimeric form of HasA from S. marcescens: DHasA. We show that both monomeric and dimeric forms are secreted in iron deficient conditions by S. marcescens. The crystal structure of DHasA reveals that it is a domain swapped dimer. The overall structure of each monomeric subunit of DHasA is very similar to that of HasA but formed by parts coming from the two different polypeptide chains, involving one of the heme ligands. Consequently DHasA binds two heme molecules by residues coming from both polypeptide chains. We show here that, while DHasA can bind two heme molecules, it is not able to deliver them to the receptor HasR. However, DHasA can efficiently transfer its heme to the monomeric form that, in turn, delivers it to HasR. We assume that DHasA can function as a heme reservoir in the hemophore system.


    Organizational Affiliation

    CNRS, Université Pierre et Marie Curie-Paris 6, Laboratoire International Associé-Dispersal and Adaptation in Marine Species, Unité Mixte de Recherche 7139, Station Biologique, F-29682 Roscoff Cedex, France.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEMOPHORE HASA
A, B
173Serratia marcescensMutation(s): 0 
Gene Names: hasA
Find proteins for Q54450 (Serratia marcescens)
Go to UniProtKB:  Q54450
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
HEM
Query on HEM

Download SDF File 
Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.169 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 47.080α = 90.00
b = 62.320β = 105.34
c = 56.820γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-05-26
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance