BPS2026 – A case study of EPR distance measurements for drug development: Elucidating dimerization dynamics via DEER spectroscopy

Protein dimerization, a type of protein-protein interaction, is a significant area of interest in pharmaceutical and drug-discovery industries. Because dimerization influences and regulates many key protein categories such as enzymes, ion channels, and transcription factors, they play a vital role in many biological and physiological processes that make appealing therapeutic targets. Therefore, understanding the mechanism of interaction is of significant interest to the scientific community. Likewise, developing techniques and methodologies to gain deeper insight into these processes provides scientists with a more expansive toolbox from which to draw from. double electron electron resonance (DEER) is one such tool, which utilizes electron paramagnetic resonance (EPR) to measure nanoscale distances between unpaired electron spins within a macromolecular structure. DEER is sensitive to the number of coupled spins within a molecular body, making it a capable tool for monitoring the dimerization and assembly of supramolecular structures. Here, we present a case study of a homodimeric protein, using DEER to monitor and determine the structure, dynamics, and equilibrium of dimerization in the context of varying buffer conditions and additives. This work represents the application of EPR distance techniques to relevant biological problems of interest to the broad scientific community, with direct applicability in pharmaceutical and biotechnology workflows.