Multidomain Protein-Urea Interactions: Differences in Binding Behavior Lead to Different Destabilization Tendencies...

Area of Science:

• Biochemistry
• Computational Biology
• Pharmaceutical Sciences

Background:

• Monoclonal antibodies (mAbs) are crucial therapeutics, but their stability is affected by formulation excipients like urea.
• Understanding protein-cosolute interactions is vital for developing stable antibody formulations.
• Complex multi-domain proteins like mAbs present challenges for experimental stability analysis.

Purpose of the Study:

• To investigate the influence of urea on monoclonal antibody (mAb) stability.
• To elucidate the domain-specific interactions between urea and mAbs.
• To explore the utility of molecular dynamics (MD) simulations and Kirkwood-Buff theory in studying protein-cosolute interactions.

Main Methods:

• Combined use of molecular dynamics (MD) simulations and differential scanning fluorimetry (DSF).
• Analysis of protein-urea binding at the domain level.
• Application of Kirkwood-Buff theory to interpret simulation data.

Main Results:

• Urea, a denaturing cosolute, binds strongly to mAbs, promoting denaturation and aggregation at elevated temperatures.
• Protein-urea interactions are domain-specific, influenced by individual mAb domain surface properties.
• Lennard-Jones interactions were identified as the primary drivers of significant urea binding to mAbs.

Conclusions:

• MD simulations coupled with Kirkwood-Buff theory can effectively dissect domain-specific protein-cosolute interactions.
• This approach aids in understanding and predicting the behavior of multi-domain proteins in the presence of formulation excipients.
• The findings support the use of computational methods in antibody drug discovery and formulation development.