Inducing protein aggregation by extensional flow

Area of Science:

• Biophysics
• Protein Chemistry
• Chemical Engineering

Background:

• Hydrodynamic flow fields' impact on protein stability is poorly understood.
• Protein aggregation occurs in nature and during industrial manufacturing.
• Relationships between flow, protein structure, and aggregation are unclear.

Purpose of the Study:

• Assess extensional flow effects on protein aggregation.
• Investigate aggregation of BSA, β2m, G-CSF, and mAbs.
• Determine factors influencing flow-induced protein aggregation.

Main Methods:

• Utilized a defined, quantified extensional flow field.
• Exposed various proteins to flow for 0.36-1.8 ms.
• Measured aggregation at low protein concentrations (0.5 mg mL-1).
• Demonstrated in situ labeling of buried cysteine in BSA under stress.

Main Results:

• Extensional flow induced aggregation in multiple proteins.
• Aggregation extent depended on strain rate, protein concentration, structure, and sequence.
• Flow readily unfolded stable proteins, exposing aggregation-prone regions.
• Aggregation occurred rapidly (0.36-1.8 ms) at low concentrations.

Conclusions:

• Extensional flow is a significant factor in protein aggregation.
• Protein sequence and structure dictate susceptibility to flow-induced unfolding and aggregation.
• Understanding these mechanisms is crucial for protein manufacturing and stability.