Characterizing Protein Dynamics with NMR R 1 ρ Relaxation Experiments

: The measurement of R1ρ , the longitudinal relaxation rate constant in the rotating frame, is one of the few available methods to characterize the μs-ms functional dynamics of biomolecules. Here, we focus on 15N R1ρ experiments for protein NH groups. We present protocols for both on- and off-resonance 15N R1ρ measurements needed for relaxation dispersion studies, and describe the data analysis for extracting kinetic and thermodynamic parameters characterizing the motional processes.