Mechanically transduced immunosorbent assay to measure protein-protein interactions
Christopher J Petell,
Kathyrn Randene,
Michael Pappas,
Diego Sandoval,
Brian D Strahl,
Joseph S Harrison,
Joshua P Steimel
Affiliations
Christopher J Petell
Department of Biochemistry and Biophysics, The University of North Carolina School of Medicine, Chapel Hill, United States; UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, United States
Kathyrn Randene
Department of Chemistry, University of the Pacific, Stockton, United States
Michael Pappas
Department of Biological Engineering, University of the Pacific, Stockton, United States
Diego Sandoval
Department of Biological Engineering, University of the Pacific, Stockton, United States
Department of Biochemistry and Biophysics, The University of North Carolina School of Medicine, Chapel Hill, United States; UNC Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, United States
Measuring protein-protein interaction (PPI) affinities is fundamental to biochemistry. Yet, conventional methods rely upon the law of mass action and cannot measure many PPIs due to a scarcity of reagents and limitations in the measurable affinity ranges. Here, we present a novel technique that leverages the fundamental concept of friction to produce a mechanical signal that correlates to binding potential. The mechanically transduced immunosorbent (METRIS) assay utilizes rolling magnetic probes to measure PPI interaction affinities. METRIS measures the translational displacement of protein-coated particles on a protein-functionalized substrate. The translational displacement scales with the effective friction induced by a PPI, thus producing a mechanical signal when a binding event occurs. The METRIS assay uses as little as 20 pmols of reagents to measure a wide range of affinities while exhibiting a high resolution and sensitivity. We use METRIS to measure several PPIs that were previously inaccessible using traditional methods, providing new insights into epigenetic recognition.
