Nuclear spin relaxation originates from the fluctuations of interactions due to motions at the molecular scales. Relaxation rates encode precious information about these motions, such as: overall rotational diffusion, librations, jumps between distinct rotamers, etc. The information on molecular motions is only probed at the resonance frequencies of nuclear spins. Thus, a measurement at a single high-field, as possible on most NMR spectrometers, provides limited information about molecular motions. Our objective is to maximize the information from relaxation in order to probe a broad range of processes. We achieve this goal by measuring relaxation over a broad range of magnetic fields by simply moving the NMR sample in the stray field of the magnet, in a fast and controlled way, so that we can still measure high-quality spectra at high field. We develop and test a series of prototype systems with the company Bruker Biospin.

We use this system to determine the internal dynamics in large enzymes to understand allosteric communication, disordered proteins to understand their weak interactions, and nucleic acids.

We also exploit this system to probe interactions of small molecules with macromolecules to detect metabolite-protein interactions in biological fluids, or inhibitor-enzyme complexes.