Predicting Salt Effects on the Binding of PFAS to Protein

Area of Science:

• Environmental Chemistry
• Toxicology
• Biochemistry

Background:

• Per- and polyfluoroalkyl substances (PFAS) accumulate in tissues by binding to proteins, causing adverse health effects.
• The influence of salts on PFAS-protein interactions, critical for environmental and biological systems, remains largely unexamined.

Purpose of the Study:

• To investigate the impact of salt on the binding affinity between various anionic PFAS and bovine serum albumin (BSA).
• To explore how factors like PFAS structure, salt composition, ionic strength, and pH modulate these interactions.
• To develop a predictive model for PFAS binding affinity under different salinity conditions.

Main Methods:

• Studied interactions of anionic PFAS (e.g., PFOA, PFOS, GenX) with BSA across a range of salt conditions.
• Analyzed binding affinity dependence on PFAS chain length, headgroup, salt type, ionic strength, and pH.
• Employed thermodynamic analysis to elucidate interaction mechanisms.
• Developed a predictive model for PFAS-BSA binding affinity.

Main Results:

• PFAS/BSA binding affinity is modulated by PFAS molecular structure, salt composition, ionic strength, and pH.
• Increased ionic strength and decreased cation valency weakened PFAS/BSA interactions.
• Salt effects on binding were more pronounced at lower pH.
• Thermodynamic analysis revealed a hydrophobic-dominant interaction mechanism.
• A model was developed to predict PFAS binding, showing significant salt influence on wastewater association.

Conclusions:

• Salt concentration and composition are critical determinants of PFAS-protein interactions.
• The developed model provides insights into PFAS environmental distribution and potential toxicity, influenced by salinity.
• This research highlights the importance of considering salt effects in environmental risk assessments of PFAS.