1M71

Crystal structure of a Monoclonal Fab Specific for Shigella Flexneri Y lipopolysaccharide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.223 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Molecular Recognition of Oligosaccharide Epitopes by a Monoclonal Fab Specific for Shigella flexneri Y Lipopolysaccharide: X-ray Structures and Thermodyanamics

Vyas, N.K.Vyas, M.N.Chervenak, M.C.Johnson, M.A.Pinto, B.M.Bundle, D.R.Quiocho, F.A.

(2002) Biochemistry 41: 13575-13586

  • Primary Citation of Related Structures:  1M7D, 1M7I

  • PubMed Abstract: 
  • The antigenic recognition of Shigella flexneri O-polysaccharide, which consists of a repeating unit ABCD [-->2)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1-->], by the monoclonal antibody SYA/J6 (IgG3, kappa) has ...

    The antigenic recognition of Shigella flexneri O-polysaccharide, which consists of a repeating unit ABCD [-->2)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->3)-alpha-L-Rhap-(1-->3)-beta-D-GlcpNAc-(1-->], by the monoclonal antibody SYA/J6 (IgG3, kappa) has been investigated by crystallographic analysis of the Fab domain and its two complexes with two antigen segments (a pentasaccharide Rha A-Rha B-Rha C-GlcNAc D-Rha A' and a modified trisaccharide Rha B-Rha C-GlcNAc D in which Rha C* is missing a C2-OH group). These complex structures, the first for a Fab specific for a periodic linear heteropolysaccharide, reveal a binding site groove (between the V(H) and V(L) domains) that makes polar and nonpolar contacts with all the sugar residues of the pentasaccharide. Both main-chain and side-chain atoms of the Fab are used in ligand binding. The charged side chain of Glu H50 of CDR H2 forms crucial hydrogen bonds to GlcNAc of the oligosaccharides. The modified trisaccharide is more buried and fits more snugly than the pentasaccharide. It also makes as many contacts (approximately 75) with the Fab as the pentasaccharide, including the same number of hydrogen bonds (eight, with four being identical). It is further engaged in more hydrophobic interactions than the pentasaccharide. These three features favorable to trisaccharide binding are consistent with the observation of a tighter complex with the trisaccharide than the pentasaccharide. Thermodynamic data demonstrate that the native tri- to pentasaccharides have free energies of binding in the range of 6.8-7.4 kcal mol(-1), and all but one of the hydrogen bonds to individual hydroxyl groups provide no more than approximately 0.7 kcal mol(-1). They further indicate that hydrophobic interactions make significant contributions to binding and, as the native epitope becomes larger across the tri-, tetra-, pentasaccharide series, entropy contributions to the free energy become dominant.


    Related Citations: 
    • Preliminary Crystallographic Analysis of a Fab Specific for the O-antigen of Shigella flexneri Cell Surface Lipopolysaccharide with and without Bound Saccharides
      Vyas, N.K.,Vyas, M.N.,Meikkle, P.J.,Sinnott, B.,Pinto, B.M.,Bundle, D.R.,Quiocho, F.A.
      (1993) J.Mol.Biol. 231: 133


    Organizational Affiliation

    Verna and Marrs Mclean Department of Biochemistry and Molecular Biology and Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
light chain of the monoclonal antibody Fab SYA/J6
A
215Mus musculusGene Names: Igkc (Igk-C)
Find proteins for A2NHM3 (Mus musculus)
Go to UniProtKB:  A2NHM3
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
heavy chain of the monoclonal antibody Fab SYA/J6
B
220Mus musculusN/A
Find proteins for P01801 (Mus musculus)
Go to UniProtKB:  P01801
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.291 
  • R-Value Work: 0.223 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 70.700α = 90.00
b = 70.700β = 90.00
c = 202.400γ = 90.00
Software Package:
Software NamePurpose
MERLOTphasing
CNSrefinement
WEISdata scaling
Weissenbergdata collection
WEISSENBERGdata reduction
WEISdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-07-22
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance