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The structural basis of antigen-antibody recognition
Annual Review of Biophysics and Biophysical Chemistry
|January 1, 1987
Summary
This study reveals the three-dimensional structure of a hen egg-white lysozyme (HEL) and antibody fragment (Fab) complex using X-ray crystallography. The antigen-antibody interface shows specific interactions, highlighting the antibody's fine recognition of HEL's topographical determinant.
Area of Science:
- Structural biology
- Immunology
- Biochemistry
Background:
- Hen egg-white lysozyme (HEL) is a well-characterized protein antigen.
- Murine monoclonal anti-HEL antibody Fab fragment was generated for complex formation.
Purpose of the Study:
- To determine the three-dimensional structure of the HEL-Fab complex.
- To analyze the molecular interactions at the antigen-antibody interface.
Main Methods:
- X-ray crystallography was employed to resolve the complex structure at 2.8-A resolution.
- Three-dimensional model building utilized electron-density maps and amino-acid sequences.
Main Results:
- The complex structure revealed 17 antibody residues interacting with 16 HEL residues, primarily within complementarity-determining regions.
- The HEL epitope is a discontinuous, topographical determinant.
- Antigen-antibody contacts involve van der Waals forces and hydrogen bonds, indicating specific recognition sensitive to antigenic variation.
Conclusions:
- The antibody exhibits fine specificity for HEL, influenced by antigenic variation.
- No significant conformational changes were observed in either HEL or the Fab upon complex formation.