Multimodal (MM) Chromatography offers highly selective protein separation systems by taking advantage of hydrophobic, electrostatic and Van der Waals interactions. Due to the complexity of such protein-ligand interactions there is a need for the molecular level understanding of the nature of proteins binding to different MM chromatographic systems. In addition, it is important to understand the thermodynamics of these interactions, particularly the relative contributions of various entropic and enthalpic components under different conditions. In this work, SPR is employed to study the interactions of protein libraries with SAMs presenting various MM cation exchange ligand head groups at different ligand densities. These experiments were carried out over a range of temperatures to determine the entropic and enthalpic contributions toward binding in each protein-MM system. This data is then analyzed to determine relationships between certain thermodynamic behavior and protein/ligand properties. Further, the impact of ligand density on transitions between different thermodynamic behaviors is examined. The change in thermodynamic driving forces that occur in the presence of fluid phase modifiers (FPMs) that disrupt hydrophobic and/or electrostatic interactions is also examined. This work demonstrates the utility of an SPR based approach for evaluating protein binding thermodynamics in multimodal systems and provides new understanding of selectivity in these systems.

Investigation into thermodynamic binding mechanisms of protein-ligand interactions in MM chromatography using surface plasmon resonance

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.