The second virial coefficient as a predictor of protein aggregation propensity: A self-interaction chromatography...

Area of Science:

• Biochemistry
• Protein Science
• Physical Chemistry

Background:

• Protein aggregation is a critical concern in biopharmaceutical development.
• Understanding protein-protein interactions is key to controlling aggregation.
• The second osmotic virial coefficient (b2) is a measure of these interactions.

Purpose of the Study:

• To measure b2 for four different proteins under various solution conditions.
• To investigate the relationship between b2 and protein aggregate size.
• To assess the utility of b2 as a predictor of protein aggregation propensity.

Main Methods:

• Self-interaction chromatography (SIC) was used to determine b2 values.
• Dynamic light scattering (DLS) measured protein aggregate sizes.
• Experiments were conducted across varying salt types, concentrations, and pH levels.

Main Results:

• A linear correlation was found between b2 values and protein aggregate hydrodynamic size for all proteins studied.
• Non-aggregated protein systems (<∼10nm) consistently showed positive b2 values (>0).
• Protein-dependent trends in b2 were observed, indicating specific interaction behaviors.

Conclusions:

• Quantifying protein-protein interactions via b2 is a valuable screening tool.
• SIC-derived b2 data can help predict protein aggregation propensity.
• This approach offers insights into protein stability and formulation development.