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Conformational correction mechanisms aiding antigen recognition by a humanized antibody
M A Holmes1, T N Buss, J Foote
1Division of Molecular Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA.
The Journal of Experimental Medicine
|March 28, 1998
Summary
The crystal structure reveals how humanized antibodies adapt their antigen-binding sites. This antibody engineering process corrects conformational changes for effective hen egg lysozyme binding.
Area of Science:
- Structural biology
- Immunology
- Protein engineering
Background:
- Antibody engineering aims to improve therapeutic properties.
- Humanization can introduce conformational changes in antibody binding sites.
- Understanding these changes is crucial for antibody design.
Purpose of the Study:
- To determine the crystal structure of a hen egg lysozyme-antibody complex.
- To compare the antigen-binding site conformations of mouse and humanized antibodies.
- To elucidate the mechanism of conformational adaptation during antigen binding.
Main Methods:
- X-ray crystallography at 2.7-A resolution.
- Structural analysis of protein-protein complexes.
- Comparison of antibody Fv fragment structures.
Main Results:
- The crystal structure of hen egg lysozyme complexed with a humanized antilysozyme antibody Fv fragment was determined.
- The antigen-combining site in the complexed humanized antibody closely resembles the parent mouse antibody.
- Unliganded mouse and humanized antibodies exhibit distinct binding site conformations.
Conclusions:
- Antigen binding induces a conformational readjustment in the humanized antibody.
- This process corrects adverse conformations in complementarity-determining regions introduced during engineering.
- Structural insights guide the rational design of humanized antibodies.