A biophysical toolkit for molecular interactions

Abstract

Intermolecular interactions inside and around the cell are key to maintain basic cell homeostasis and to sense and react to external stimuli. Moreover, the action of therapeutics and other xenobiotics occurs through physical interactions of these agents with biomolecules present in the cell or tissue, thereby interfering with the ‘native’ interactions of the biomolecules. Biophysical characterisation of molecular interactions is a bottom‐up reductionist approach that implies measuring the physicochemical properties of the interacting species (two biomacromolecules or a biomacromolecule and a small‐molecule ligand) in order to quantify the binding strength (thermodynamics) and association and dissociation speed (kinetics) between them. A large variety of macroscopic experimental techniques are available and constitute a biophysical toolkit to study molecular interactions in vitro. Among others, isothermal titration calorimetry, surface plasmon resonance, analytical ultracentrifugation, nuclear magnetic resonance, microscale thermophoresis, thermal shift and fluorescence‐based methods are most commonly used.