X-ray structure of the uncomplexed anti-tumor antibody BR96 and comparison with its antigen-bound form

J Mol Biol. 1996 Jun 28;259(5):938-46. doi: 10.1006/jmbi.1996.0371.


The X-ray structure of the uncomplexed human chimeric Fab' of the anti-tumor antibody BR96 has been determined at 2.6 A resolution. The structure has been compared with Lewis Y antigen-complexed structures of BR96 which were determined previously. The comparison reveals segmental motions and/or conformational rearrangements of three CDR loops (L1, L3, and H2), whereas CDR H3 does not undergo changes upon complexation despite its significant main-chain contacts to the carbohydrate antigen. In light of the uncomplexed chimeric Fab' structure reported here, the previously observed high mobility of the CL:CH1 domains of the complexed chimeric BR96 Fab is rationalized as a "swinging" motion approximately about the axis of the elbow bend.

MeSH terms

  • Animals
  • Antibodies, Neoplasm / chemistry*
  • Antibodies, Neoplasm / immunology
  • Antigen-Antibody Reactions
  • Antigens, Neoplasm / chemistry*
  • Antigens, Neoplasm / immunology
  • Carbohydrate Sequence
  • Crystallography, X-Ray
  • Humans
  • Immunoglobulin Fab Fragments / chemistry*
  • Immunoglobulin Fab Fragments / immunology
  • Lewis Blood Group Antigens / immunology
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / immunology


  • Antibodies, Neoplasm
  • Antigens, Neoplasm
  • Immunoglobulin Fab Fragments
  • Lewis Blood Group Antigens
  • Lewis Y antigen
  • Recombinant Fusion Proteins