4OTX

Structure of the anti-Francisella tularensis O-antigen antibody N203 Fab fragment


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

Functional and Structural Characterization of Francisella tularensis O-Antigen Antibodies at the Low End of Antigen Reactivity.

Lu, Z.Rynkiewicz, M.J.Yang, C.Y.Madico, G.Perkins, H.M.Roche, M.I.Seaton, B.A.Sharon, J.

(2014) Monoclon Antib Immunodiagn Immunother 33: 235-245

  • DOI: 10.1089/mab.2014.0022
  • Primary Citation of Related Structures:  
    4OTX

  • PubMed Abstract: 
  • The O-antigen (OAg) of the Gram-negative bacterium Francisella tularensis (Ft), which is both a capsular polysaccharide and a component of lipopolysaccharide, is comprised of tetrasaccharide repeats and induces antibodies mainly against repeating internal epitopes ...

    The O-antigen (OAg) of the Gram-negative bacterium Francisella tularensis (Ft), which is both a capsular polysaccharide and a component of lipopolysaccharide, is comprised of tetrasaccharide repeats and induces antibodies mainly against repeating internal epitopes. We previously reported on several BALB/c mouse monoclonal antibodies (MAbs) that bind to internal Ft OAg epitopes and are protective in mouse models of respiratory tularemia. We now characterize three new internal Ft OAg IgG2a MAbs, N203, N77, and N24, with 10- to 100-fold lower binding potency than previously characterized internal-OAg IgG2a MAbs, despite sharing one or more variable region germline genes with some of them. In a mouse model of respiratory tularemia with the highly virulent Ft type A strain SchuS4, the three new MAbs reduced blood bacterial burden with potencies that mirror their antigen-binding strength; the best binder of the new MAbs, N203, prolonged survival in a dose-dependent manner, but was at least 10-fold less potent than the best previously characterized IgG2a MAb, Ab52. X-ray crystallographic studies of N203 Fab showed a flexible binding site in the form of a partitioned groove, which cannot provide as many contacts to OAg as does the Ab52 binding site. These results reveal structural features of antibodies at the low end of reactivity with multi-repeat microbial carbohydrates and demonstrate that such antibodies still have substantial protective effects against infection.


    Organizational Affiliation

    1 Department of Pathology and Laboratory Medicine, Boston University School of Medicine , Boston, Massachusetts.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
N203 light chainA [auth L], C [auth M]219Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
N203 heavy chainB [auth H], D [auth I]213Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
AZI
Query on AZI

Download Ideal Coordinates CCD File 
K [auth M]AZIDE ION
N3
IVRMZWNICZWHMI-UHFFFAOYSA-N
 Ligand Interaction
CL
Query on CL

Download Ideal Coordinates CCD File 
E [auth L] , F [auth L] , G [auth L] , H [auth L] , I [auth H] , J [auth H] , L [auth M] , M , 
E [auth L],  F [auth L],  G [auth L],  H [auth L],  I [auth H],  J [auth H],  L [auth M],  M,  N [auth M],  O [auth M],  P [auth M],  Q [auth M],  R [auth M],  S [auth M],  T [auth I],  U [auth I],  V [auth I],  W [auth I]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PCA
Query on PCA
B [auth H], D [auth I]L-PEPTIDE LINKINGC5 H7 N O3GLN
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.228 
  • R-Value Work: 0.193 
  • R-Value Observed: 0.194 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 66.011α = 90
b = 122.322β = 90
c = 124.764γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-09-10
    Type: Initial release
  • Version 2.0: 2019-12-25
    Changes: Derived calculations, Polymer sequence