4AIP

The FrpB iron transporter from Neisseria meningitidis (F3-3 variant)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.245 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Use of a Molecular Decoy to Segregate Transport from Antigenicity in the Frpb Iron Transporter from Neisseria Meningitidis

Saleem, M.Prince, S.M.Rigbb, S.E.J.Imran, M.Patel, H.Chan, H.Sanders, H.Maiden, M.C.J.Feavers, I.M.Derrick, J.P.

(2013) PLoS One 8: 57646

  • DOI: 10.1371/journal.pone.0056746
  • Primary Citation of Related Structures:  
    4B7O, 4AIP, 4AIQ

  • PubMed Abstract: 
  • FrpB is an outer membrane transporter from Neisseria meningitidis, the causative agent of meningococcal meningitis. It is a member of the TonB-dependent transporter (TBDT) family and is responsible for iron uptake into the periplasm. FrpB is subject to a high degree of antigenic variation, principally through a region of hypervariable sequence exposed at the cell surface ...

    FrpB is an outer membrane transporter from Neisseria meningitidis, the causative agent of meningococcal meningitis. It is a member of the TonB-dependent transporter (TBDT) family and is responsible for iron uptake into the periplasm. FrpB is subject to a high degree of antigenic variation, principally through a region of hypervariable sequence exposed at the cell surface. From the crystal structures of two FrpB antigenic variants, we identify a bound ferric ion within the structure which induces structural changes on binding which are consistent with it being the transported substrate. Binding experiments, followed by elemental analysis, verified that FrpB binds Fe(3+) with high affinity. EPR spectra of the bound Fe(3+) ion confirmed that its chemical environment was consistent with that observed in the crystal structure. Fe(3+) binding was reduced or abolished on mutation of the Fe(3+)-chelating residues. FrpB orthologs were identified in other Gram-negative bacteria which showed absolute conservation of the coordinating residues, suggesting the existence of a specific TBDT sub-family dedicated to the transport of Fe(3+). The region of antigenic hypervariability lies in a separate, external sub-domain, whose structure is conserved in both the F3-3 and F5-1 variants, despite their sequence divergence. We conclude that the antigenic sub-domain has arisen separately as a result of immune selection pressure to distract the immune response from the primary transport function. This would enable FrpB to function as a transporter independently of antibody binding, by using the antigenic sub-domain as a 'molecular decoy' to distract immune surveillance.


    Related Citations: 
    • Refolding, Purification and Crystallization of the Frpb Outer Membrane Iron Transporter from Neisseria Meningitidis.
      Saleem, M., Prince, S.M., Patel, H., Chan, H., Feavers, I.M., Derrick, J.P.
      (2012) Acta Crystallogr Sect F Struct Biol Cryst Commun 68: 231

    Organizational Affiliation

    Michael Smith Building, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, United Kingdom.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
FE-REGULATED PROTEIN BA, B, C742Neisseria meningitidisMutation(s): 0 
Gene Names: frpB
Membrane Entity: Yes 
UniProt
Find proteins for Q51162 (Neisseria meningitidis)
Explore Q51162 
Go to UniProtKB:  Q51162
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
N8E
Query on N8E

Download Ideal Coordinates CCD File 
E [auth A], F [auth B]3,6,9,12,15-PENTAOXATRICOSAN-1-OL
C18 H38 O6
MJELOWOAIAAUJT-UHFFFAOYSA-N
 Ligand Interaction
GLU
Query on GLU

Download Ideal Coordinates CCD File 
D [auth A]GLUTAMIC ACID
C5 H9 N O4
WHUUTDBJXJRKMK-VKHMYHEASA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.296 
  • R-Value Work: 0.242 
  • R-Value Observed: 0.245 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.32α = 90
b = 104.62β = 90
c = 269.1γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-01-23
    Type: Initial release
  • Version 1.1: 2013-03-06
    Changes: Database references, Structure summary
  • Version 1.2: 2013-04-03
    Changes: Database references