Probing single-molecule protein conformational dynamics.

Protein conformational fluctuations and dynamics, often complex and associated with inhomogeneities, play a crucial role in biomolecular functions. It is extremely difficult to characterize such inhomogeneous dynamics in an ensemble-averaged measurement, especially when the proteins are involved in multiple-step, multiple-conformation complex chemical interactions and transformations, such as in enzymatic reactions, protein-protein interactions, and ion-channel membrane protein processes. Alternatively, single-molecule spectroscopy is a powerful approach to probing and analyzing protein conformational dynamics in real time.