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Updated: Apr 15, 2026
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Identification of Functional Protein Regions Through Chimeric Protein Construction
Published on: January 8, 2019
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Structure of the omalizumab Fab
Rasmus K Jensen1, Melanie Plum1, Luna Tjerrild1
1Department of Molecular Biology and Genetics, Aarhus University, Gustav Wiedsvej 10C, 8000 Aarhus, Denmark.
Summary
Omalizumab, an anti-IgE antibody, targets immunoglobulin E (IgE) to treat allergic conditions. Structural analysis reveals how omalizumab binds IgE, providing a basis for its therapeutic function and potential optimization.
Area of Science:
- Immunology
- Structural Biology
- Biochemistry
Background:
- Omalizumab is a humanized anti-IgE antibody inhibiting IgE-mediated inflammation.
- The precise binding epitope and conformational mechanisms of omalizumab-IgE interaction are unknown.
Purpose of the Study:
- To elucidate the molecular mechanism of omalizumab's anti-IgE activity.
- To determine the structural basis of omalizumab binding to human IgE.
Main Methods:
- Recombinant production of human IgE Fc (Cε2-4) in HEK-293 cells.
- Purification of omalizumab Fab fragments after papain cleavage.
- Size-exclusion chromatography for complex preparation.
- X-ray crystallography of omalizumab Fab.
Main Results:
- Two crystal structures of omalizumab Fab were determined at 1.9 and 3.0 Å resolution.
- The structures reveal the arrangement of complementarity-determining regions (CDRs) and key binding residues.
- Crystallization of the IgE Fc-Omalizumab complex was unsuccessful due to protein dissociation.
Conclusions:
- The determined structures provide a structural basis for understanding omalizumab's anti-IgE function.
- Findings offer insights for optimizing complex crystallization and future drug design.
- The study raises questions about conformational requirements for effective anti-IgE activity.
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