Experimental Data Snapshot

  • Resolution: 1.60 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.179 

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Structure of Haemophilus influenzae Fe(+3)-binding protein reveals convergent evolution within a superfamily.

Bruns, C.M.Nowalk, A.J.Arvai, A.S.McTigue, M.A.Vaughan, K.G.Mietzner, T.A.McRee, D.E.

(1997) Nat Struct Biol 4: 919-924

  • DOI: https://doi.org/10.1038/nsb1197-919
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The first crystal structure of the iron-transporter ferric ion-binding protein from Haemophilus influenzae (hFBP), at 1.6 A resolution, reveals the structural basis for iron uptake and transport required by several important bacterial pathogens. Paradoxically, although hFBP belongs to a protein superfamily which includes human transferrin, iron binding in hFBP and transferrin appears to have developed independently by convergent evolution. Structural comparison of hFBP with other prokaryotic periplasmic transport proteins and the eukaryotic transferrins suggests that these proteins are related by divergent evolution from an anion-binding common ancestor, not from an iron-binding ancestor. The iron binding site of hFBP incorporates a water and an exogenous phosphate ion as iron ligands and exhibits nearly ideal octahedral metal coordination. FBP is highly conserved, required for virulence, and is a nodal point for free iron uptake in several Gram-negative pathogenic bacteria, thus providing a potential target for broad-spectrum antibacterial drug design against human pathogens such as H. influenzae, Neisseria gonorrhoeae, and Neisseria meningitidis.

  • Organizational Affiliation

    Department of Molecular Biology MB8, Scripps Research Institute, La Jolla, California 92037, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
FERRIC IRON BINDING PROTEIN309Haemophilus influenzaeMutation(s): 0 
Gene Names: hitA
Find proteins for P35755 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd))
Explore P35755 
Go to UniProtKB:  P35755
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP35755
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.60 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.179 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 132.194α = 90
b = 52.449β = 90
c = 41.255γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-01-28
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance