Structure and Dynamics of Monoclonal Antibody Domains Using Spins, Scattering, and Simulations

Area of Science:

• Biochemistry
• Structural Biology
• Biotechnology

Background:

• Antibody-based biologics represent a dominant and growing pharmaceutical platform.
• Current understanding of inter-domain structural distributions in antibodies is limited, hindering innovation.
• Accurate structural data is crucial for the development of novel antibody therapeutics.

Purpose of the Study:

• To develop and validate a novel methodology for determining biomolecular structure ensembles of antibodies.
• To address the knowledge gap in inter-domain structural distributions of monoclonal antibodies (mAbs).
• To enable simultaneous determination of structural distributions and dynamics of mAb-based biologics.

Main Methods:

• Utilized a library of tagged proteins (spin-labeled affinity protein reagents - SLAP) to probe an unlabeled target biologic.
• Employed double electron-electron resonance (DEER) spectroscopy to measure inter-spin distance distributions.
• Integrated molecular simulations with DEER and solution X-ray scattering measurements.

Main Results:

• Successfully determined inter-spin distance distributions in SLAP complexes of the isolated Fc domain and intact NISTmAb.
• Demonstrated the general applicability and extendability of SLAP reagents for immunoglobulin G (IgG) class mAbs.
• Enabled simultaneous determination of structural distributions and dynamics through integrated computational and experimental approaches.

Conclusions:

• The developed methodology provides a powerful tool for characterizing antibody structures and dynamics.
• This approach can significantly advance the development and innovation of antibody-based pharmaceuticals.
• SLAP reagents offer a versatile platform for structural studies of therapeutic antibodies.