2G5G

Cofacial heme binding to ChaN of Campylobacter jejuni


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.207 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Cofacial Heme Binding is Linked to Dimerization by a Bacterial Heme Transport Protein.

Chan, A.C.Lelj-Garolla, B.Rosell, F.I.Pedersen, K.A.Mauk, A.G.Murphy, M.E.

(2006) J.Mol.Biol. 362: 1108-1119

  • DOI: 10.1016/j.jmb.2006.08.001

  • PubMed Abstract: 
  • Campylobacter jejuni is a leading bacterial cause of food-borne illness in the developed world. Like most pathogens, C. jejuni requires iron that must be acquired from the host environment. Although the iron preference of the food-borne pathogen C. j ...

    Campylobacter jejuni is a leading bacterial cause of food-borne illness in the developed world. Like most pathogens, C. jejuni requires iron that must be acquired from the host environment. Although the iron preference of the food-borne pathogen C. jejuni is not established, this organism possesses heme transport systems to acquire iron. ChaN is an iron-regulated lipoprotein from C. jejuni proposed to be associated with ChaR, an outer-membrane receptor. Mutation of PhuW, a ChaN orthologue in Pseudomonas aeruginosa, compromises growth on heme as a sole iron source. The crystal structure of ChaN, determined to 1.9 A resolution reveals that ChaN is comprised of a large parallel beta-sheet with flanking alpha-helices and a smaller domain consisting of alpha-helices. Unexpectedly, two cofacial heme groups ( approximately 3.5 A apart with an inter-iron distance of 4.4 A) bind in a pocket formed by a dimer of ChaN monomers. Each heme iron is coordinated by a single tyrosine from one monomer, and the propionate groups are hydrogen bonded by a histidine and a lysine from the other monomer. Sequence analyses reveal that these residues are conserved among ChaN homologues from diverse bacterial origins. Electronic absorption and electron paramagnetic resonance (EPR) spectroscopy are consistent with heme binding through tyrosine coordination by ChaN in solution yielding a high-spin heme iron structure in a pH-dependent equilibrium with a low-spin species. Analytical ultracentrifugation demonstrates that apo-ChaN is predominantly monomeric and that dimerization occurs with heme binding such that the stability constant for dimer formation increases by 60-fold.


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
putative lipoprotein
X
268Campylobacter jejuni subsp. jejuni serotype O:2 (strain ATCC 700819 / NCTC 11168)Mutation(s): 0 
Find proteins for Q0PBW2 (Campylobacter jejuni subsp. jejuni serotype O:2 (strain ATCC 700819 / NCTC 11168))
Go to UniProtKB:  Q0PBW2
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
X
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
X
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.207 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 87.918α = 90.00
b = 58.790β = 119.21
c = 82.395γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
RESOLVEphasing
SCALEPACKdata scaling
SOLVEphasing
PDB_EXTRACTdata extraction
DENZOdata reduction
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-10-03
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Source and taxonomy, Version format compliance
  • Version 1.3: 2017-10-18
    Type: Refinement description