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Contrasting IgG structures reveal extreme asymmetry and flexibility
Erica Ollmann Saphire1, Robyn L Stanfield, M D Max Crispin
1Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Journal of Molecular Biology
|June 8, 2002
Summary
The crystal structure of intact human IgG1 b12 reveals significant asymmetry and flexibility, offering new insights into antibody dynamics. This first-ever visualization of a full-length IgG hinge highlights unique conformational adaptations.
Area of Science:
- Structural biology
- Immunology
- Biochemistry
Background:
- Understanding the three-dimensional structure of antibodies is crucial for elucidating their function.
- Previous studies often lacked intact human IgG structures with ordered, full-length hinges.
Purpose of the Study:
- To determine and analyze the crystal structure of the intact human IgG1 b12 antibody.
- To investigate the structural basis for interdomain flexibility and hinge region conformation in human IgG.
Main Methods:
- X-ray crystallography was employed to obtain the high-resolution structure of IgG1 b12.
- Comparative structural analysis was performed against other antibody structures.
Main Results:
- The structure revealed extreme asymmetry between the Fab and Fc domains, indicating significant interdomain flexibility.
- The complete human IgG1 hinge region was visualized, showing distinct conformations for each hinge.
- Asymmetry in glycosylation of the C(H)2 domains of the Fc region was observed.
- Only one of the two potential intra-hinge disulfides was found to be formed.
Conclusions:
- The intact IgG1 b12 structure demonstrates remarkable flexibility and asymmetry, challenging previous models of antibody conformation.
- The distinct hinge conformations are essential for accommodating the varied orientations of the Fab domains.
- The findings provide critical insights into the structural dynamics of human IgG antibodies.