1AQK

THREE-DIMENSIONAL STRUCTURE OF A HUMAN FAB WITH HIGH AFFINITY FOR TETANUS TOXOID


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Work: 0.185 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Three-dimensional structure of a human Fab with high affinity for tetanus toxoid.

Faber, C.Shan, L.Fan, Z.Guddat, L.W.Furebring, C.Ohlin, M.Borrebaeck, C.A.Edmundson, A.B.

(1998) Immunotechnology 3: 253-270

  • DOI: https://doi.org/10.1016/s1380-2933(97)10003-3
  • Primary Citation of Related Structures:  
    1AQK

  • PubMed Abstract: 

    The wide range of antibody specificity and affinity results from the differing shapes and chemical compositions of their binding sites. These shapes range from discrete grooves in antibodies elicited by linear oligomers of nucleotides and carbohydrates to shallow depressions or flat surfaces for accommodation of proteins, peptides and large organic compounds. To determine the Fab structure of a high-affinity human antitoxin antibody. To explore structural features which enable the antibody to bind to intact tetanus toxoid, peptides derived from the sequence of the natural immunogen and antigenic mimics identified by combinatorial chemistry. To explain why this Fab shows a remarkable tendency to produce crystals consistently diffracting to d spacings of 1.7-1.8 A. To use this information to engineer a strong tendency to crystallize into the design of other Fabs. The protein was crystallized in hanging or sitting drops by a microseeding technique in polyethylene glycol (PEG) 8000. Crystals were subjected to X-ray analysis and the three-dimensional structure of the Fab was determined by the molecular replacement method. Interactive computer graphics were employed to fit models to electron density maps, survey the structure in multiple views and discover the crystal packing motif of the protein. Exceptionally large single crystals of this protein have been obtained, one measuring 5 x 3 x 2 mm (l x w x d). The latter was cut into six irregular pieces, each retaining the features of the original in diffracting to high resolution (1.8 A) with little decay in the X-ray beam. In an individual Fab, the active site is relatively flat and it seems likely that the protein antigen and derivative peptides are tightly held on the outer surface without significant penetration into the interior. There is no free space to accommodate even a dipeptide between VH and VL. One of the unique features of the B7-15A2 Fab is a large aliphatic ridge dominating the center of the active site. The CDR3 of the H chain contributes significantly to this ridge, as well as to adjoining regions projected to be important for the docking of the antigen. Both the ease of crystallization and the favorable diffraction properties are mainly attributable to the tight packing of the protein molecules in the crystal lattice. The B7-15A2 active site provides a stable and well defined platform for high affinity docking of proteins, peptides and their mimotopes. The advantages for future developments are suggested by the analysis of the crystal properties. It should be possible to incorporate the features promoting crystallization, close packing and resistance to radiation damage into engineered human antibodies without altering the desired specificities and affinities of their active sites.


  • Organizational Affiliation

    Oklahoma Medical Research Foundation, Oklahoma City 73104, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
FAB B7-15A2A [auth L]216Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P0DOY2 (Homo sapiens)
Explore P0DOY2 
Go to UniProtKB:  P0DOY2
GTEx:  ENSG00000211677 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DOY2
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
FAB B7-15A2B [auth H]226Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P01857 (Homo sapiens)
Explore P01857 
Go to UniProtKB:  P01857
PHAROS:  P01857
GTEx:  ENSG00000211896 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01857
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
PCA
Query on PCA
A [auth L]L-PEPTIDE LINKINGC5 H7 N O3GLN
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.84 Å
  • R-Value Work: 0.185 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.7α = 90
b = 78.6β = 104.3
c = 74.6γ = 90
Software Package:
Software NamePurpose
XENGENdata collection
XENGENdata reduction
X-PLORmodel building
TNTrefinement
X-PLORrefinement
XENGENdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-02-04
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2019-12-25
    Changes: Database references, Derived calculations, Other, Polymer sequence
  • Version 2.1: 2023-08-02
    Changes: Database references, Refinement description