1XF4

Structure of ligand-free Fab DNA-1 in space group P321 solved from crystals with perfect hemihedral twinning


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.187 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Evidence for Structural Plasticity of Heavy Chain Complementarity-determining Region 3 in Antibody-ssDNA Recognition

Schuermann, J.P.Prewitt, S.P.Davies, C.Deutscher, S.L.Tanner, J.J.

(2005) J Mol Biol 347: 965-978

  • DOI: 10.1016/j.jmb.2005.02.008
  • Primary Citation of Related Structures:  
    1XF4, 1XF3, 1XF2

  • PubMed Abstract: 
  • Anti-DNA antibodies play important roles in the pathogenesis of autoimmune diseases. They also represent a unique and relatively unexplored class of DNA-binding protein. Here, we present a study of conformational changes induced by DNA binding to an ...

    Anti-DNA antibodies play important roles in the pathogenesis of autoimmune diseases. They also represent a unique and relatively unexplored class of DNA-binding protein. Here, we present a study of conformational changes induced by DNA binding to an anti-ssDNA Fab known as DNA-1. Three crystal structures are reported: a complex of DNA-1 bound to dT3, and two structures of the ligand-free Fab. One of the ligand-free structures was determined from crystals exhibiting perfect hemihedral twinning, and the details of structure determination are provided. Unexpectedly, five residues (H97-H100A) in the apex of heavy chain complementarity-determining region 3 (HCDR3) are disordered in both ligand-free structures. Ligand binding also caused a 2-4A shift of the backbone of Tyr L92 and ordering of the L92 side-chain. In contrast, these residues are highly ordered in the Fab/dT3 complex, where Tyr H100 and Tyr H100A form intimate stacking interactions with DNA bases, and L92 forms the 5' end of the binding site. The structures suggest that HCDR3 is very flexible and adopts multiple conformations in the ligand-free state. These results are discussed in terms of induced fit and pre-existing equilibrium theories of ligand binding. Our results allow new interpretations of existing thermodynamic and mutagenesis data in terms of conformational entropy and the volume of conformational space accessible to HCDR3 in the ligand-free state. In the context of autoimmune disease, plasticity of the ligand-free antibody could provide a mechanism by which anti-DNA antibodies bind diverse host ligands, and thereby contribute to pathogenicity.


    Organizational Affiliation

    Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Fab light chainAL214Mus 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
Fab heavy chainBH230Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download CCD File 
A, L
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.183 
  • R-Value Observed: 0.187 
  • Space Group: P 3 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 179.179α = 90
b = 179.179β = 90
c = 91.985γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-12
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2017-10-11
    Changes: Advisory, Refinement description