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Updated: Jul 4, 2026
08:58
Characterization of Glycoproteins with the Immunoglobulin Fold by X-Ray Crystallography and Biophysical Techniques
Published on: July 5, 2018
Disulfide connectivity of human immunoglobulin G2 structural isoforms
Theresa Martinez1, Amy Guo, Martin J Allen
1Department of Analytical and Formulation Sciences, Process and Product Development, Amgen, Inc., Seattle, Washington 98119, USA.
Biochemistry
|June 14, 2008
Summary
The IgG2 molecule
Area of Science:
- Immunology
- Structural Biology
- Protein Chemistry
Background:
- The consensus model of human immunoglobulins G (IgGs) depicts a flexible hinge region connecting distinct Fc and Fab domains.
- This model is widely accepted for understanding IgG structure and function.
Purpose of the Study:
- To elucidate the detailed disulfide structure of IgG2 molecules.
- To investigate the unique structural organization of IgG2 compared to the consensus IgG model.
Main Methods:
- Detailed analysis of disulfide bridge connections within IgG2 molecules.
- Identification and characterization of different IgG2 structural isoforms.
- Cysteine residue mutation studies to assess the role of disulfide bonds.
Main Results:
- IgG2 molecules exhibit a unique structural organization distinct from the consensus model, featuring multiple isoforms.
- Specific disulfide bridges link IgG2 C H1 and C-terminal C L cysteine residues to each other or to IgG2-specific upper hinge cysteines.
- Each isoform possesses a unique disulfide bridge arrangement.
- Mutation of a single hinge cysteine residue disrupts these natural complexes.
Conclusions:
- The disulfide structure of IgG2 differs significantly from the conventionally accepted immunoglobulin model.
- These structural findings may explain the unique biological activities observed in the IgG2 subclass.
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