3KN7

Crystal Structure of Haemophilus influenzae Y195A mutant Holo Ferric ion-Binding Protein A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.71 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.190 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The role of vicinal tyrosine residues in the function of Haemophilus influenzae ferric binding protein A.

Khambati, H.K.Moraes, T.F.Singh, J.Shouldice, S.R.Yu, R.H.Schryvers, A.B.

(2010) Biochem.J. --: --

  • DOI: 10.1042/BJ20101043
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The periplasmic FbpA (ferric-binding protein A) from Haemophilus influenzae plays a critical role in acquiring iron from host transferrin, shuttling iron from the outer-membrane receptor complex to the inner-membrane transport complex responsible for ...

    The periplasmic FbpA (ferric-binding protein A) from Haemophilus influenzae plays a critical role in acquiring iron from host transferrin, shuttling iron from the outer-membrane receptor complex to the inner-membrane transport complex responsible for transporting iron into the cytoplasm. In the present study, we report on the properties of a series of site-directed mutants of two adjacent tyrosine residues involved in iron co-ordination, and demonstrate that, in contrast with mutation of equivalent residues in the N-lobe of human transferrin, the mutant FbpAs retain significant iron-binding affinity regardless of the nature of the replacement amino acid. The Y195A and Y196A FbpAs are not only capable of binding iron, but are proficient in mediating periplasm-to-cytoplasm iron transport in a reconstituted FbpABC pathway in a specialized Escherichia coli reporter strain. This indicates that their inability to mediate iron acquisition from transferrin is due to their inability to compete for iron with receptor-bound transferrin. Wild-type iron-loaded FbpA could be crystalized in a closed or open state depending upon the crystallization conditions. The synergistic phosphate anion was not present in the iron-loaded open form, suggesting that initial anchoring of iron was mediated by the adjacent tyrosine residues and that alternate pathways for iron and anion binding and release may be considered. Collectively, these results demonstrate that the presence of a twin-tyrosine motif common to many periplasmic iron-binding proteins is critical for initially capturing the ferric ion released by the outer-membrane receptor complex.


    Organizational Affiliation

    Department of Microbiology and Infectious Diseases, University of Calgary, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Iron-utilization periplasmic protein
A
309Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)Mutation(s): 1 
Gene Names: fbpA (fbp, hitA)
Find proteins for P35755 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd))
Go to UniProtKB:  P35755
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

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

Download SDF File 
Download CCD File 
A
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.71 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.190 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 106.464α = 90.00
b = 75.822β = 90.00
c = 34.109γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SAINTdata reduction
PROTEUM PLUSdata collection
MOLREPphasing
REFMACrefinement
SAINTdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-09-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance