James G. Kempf

Protein dynamics from solution NMR

Solution nuclear magnetic resonance (NMR) spectroscopy is unique in its ability to elucidate the details of atomic-level structural and dynamical properties of biological macromolecules under native-like conditions. Recent advances in NMR techniques and protein sample preparation now allow comprehensive investigation of protein dynamics over timescales ranging 14 orders of magnitude at nearly every atomic site. Thus, solution NMR is poised to reveal aspects of the physico-chemical properties that govern the ensemble distribution of protein conformers and the dynamics of their interconversion. We review these advances as well as their recent application to the study of proteins.

Measurement of Intermediate Exchange Phenomena

Understanding the crucial role of protein motions in the function of biological macromolecules requires methods for their characterization. These motions lead to noticeable alterations in the decay of nuclear spin magnetization. Recent advances in solution nuclear magnetic resonance (NMR) make quantitative connections between micro s-ms motions and nuclear spin relaxation in proteins. The techniques serve as useful probes of motional kinetics and thermodynamics and their relation to function. Here, we review the two most common experimental methods for characterizing conformational motions in proteins: the relaxation-compensated Carr-Purcell-Meiboom-Gill (rcCPMG) and off-resonance R1rho experiments.