1P7K

Crystal structure of an anti-ssDNA antigen-binding fragment (Fab) bound to 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.197 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of an anti-DNA fab complexed with a non-DNA ligand provides insights into cross-reactivity and molecular mimicry.

Schuermann, J.P.Henzl, M.T.Deutscher, S.L.Tanner, J.J.

(2004) Proteins 57: 269-278

  • DOI: 10.1002/prot.20200

  • PubMed Abstract: 
  • Antibodies that recognize DNA (anti-DNA) are part of the autoimmune response underlying systemic lupus erythematosus. To better understand molecular recognition by anti-DNA antibodies, crystallographic studies have been performed using an anti-ssDNA ...

    Antibodies that recognize DNA (anti-DNA) are part of the autoimmune response underlying systemic lupus erythematosus. To better understand molecular recognition by anti-DNA antibodies, crystallographic studies have been performed using an anti-ssDNA antigen-binding fragment (Fab) known as DNA-1. The previously determined structure of a DNA-1/dT5 complex revealed that thymine bases insert into a narrow groove, and that ligand recognition primarily involves the bases of DNA. We now report the 1.75-A resolution structure of DNA-1 complexed with the biological buffer HEPES (4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid). All three light chain complementarity-determining regions (CDRs) and HCDR3 contribute to binding. The HEPES sulfonate hydrogen bonds to His L91, Asn L50, and to the backbone of Tyr H100 and Tyr H100A. The Tyr side-chains of L32, L92, H100, and H100A form nonpolar contacts with the HEPES ethylene and piperazine groups. Comparison to the DNA-1/dT5 structure reveals that the dual recognition of dT5 and HEPES requires a 13-A movement of HCDR3. This dramatic structural change converts the combining site from a narrow groove, appropriate for the edge-on insertion of thymine bases, to one sufficiently wide to accommodate the HEPES sulfonate and piperazine. Isothermal titration calorimetry verified the association of HEPES with DNA-1 under conditions similar those used for crystallization (2 M ammonium sulfate). Interestingly, the presence of 2 M ammonium sulfate increases the affinities of DNA-1 for both HEPES and dT5, suggesting that non-polar Fab-ligand interactions are important for molecular recognition in highly ionic solvent conditions. The structural and thermodynamic data suggest a molecular mimicry mechanism based on structural plasticity and hydrophobic interactions.


    Related Citations: 
    • CRYSTALLIZATION AND MOLECULAR REPLACEMENT STUDIES OF A RECOMBINANT ANTIGEN-BINDING FRAGMENT COMPLEXED WITH SINGLE-STRANDED DNA
      PREWITT, S.P.,KOMISSAROV, A.A.,DEUTSCHER, S.L.,TANNER, J.J.
      (2000) Acta Crystallogr.,Sect.D 56: 1007
    • CRYSTAL STRUCTURE OF AN ANTIGEN-BINDING FRAGMENT BOUND TO SINGLE-STRANDED DNA
      TANNER, J.J.,KOMISSAROV, A.A.,DEUTSCHER, S.L.
      (2001) J.Mol.Biol. 314: 807


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
antibody light chain FAB
L, A
214Mus musculusGene Names: Igk
Find proteins for I6L978 (Mus musculus)
Go to UniProtKB:  I6L978
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
antibody heavy chain FAB
H, B
224Mus musculusGene Names: Ighg1 (Igh-4)
Find proteins for P01868 (Mus musculus)
Go to UniProtKB:  P01868
Small Molecules
Ligands 5 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EPE
Query on EPE

Download SDF File 
Download CCD File 
B, L
4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
HEPES
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B, H, L
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B, H, L
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
PEG
Query on PEG

Download SDF File 
Download CCD File 
H, L
DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
 Ligand Interaction
1PE
Query on 1PE

Download SDF File 
Download CCD File 
B, H, L
PENTAETHYLENE GLYCOL
PEG400
C10 H22 O6
JLFNLZLINWHATN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.75 Å
  • R-Value Free: 0.230 
  • R-Value Work: 0.197 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 107.666α = 90.00
b = 156.703β = 90.00
c = 61.003γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
AMoREphasing
SCALEPACKdata scaling
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-05-11
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Non-polymer description, Version format compliance