Energy Landscape We investigate functional consequences of conformational energy landscapes in proteins. Conformational energy landscapes dictate how proteins acquire its three-dimensional structures (protein folding), how proteins function (catalysis and binding), and how proteins are degraded (protein turnover) . Proteolysis is an excellent probe to monitor conformaitonal energy landscapes in proteins, especially partially unfolded states. Using protein engineering and proteolysis kinetics, we decipher the elusive structures of partially unfolded states in proteins.
Proteome Different from conventional biophysical studies on proteins, we employ proteomics approach extensively to investigate energetic and structural properties of proteins on a proteomic scale. Using proteolysis as a structural probe, we can monitor folding and unfolding of many proteins in cell lysates at the same time. We are currently developing a novel methodology for drug target identification based on this proteomics method. Identifying proteins interacting with drugs out of thousants of proteins in a proteome is a very challenging task. By measuring changes in proteins stability on a proteomic scale upon drug binding, we are attempting to identify cellular drug targets.
Pulse Proteolysis Pulse proteolysis is a facile technique to monitor protein folding and unfolding by exploiting the difference in proteolytic susceptiblity between folded and unfolded proteins. This technique allows us to study energetic properties of proteins under unconventional conditions, such as in crude cell lysates. We rutinely determine protein stability without purifying proteins from cell lysates. This approach must be quite useful with proteins hard to express or purify, such as membrane proteins. We are currently attempting to monitor folding and unfolding of membrane proteins without purifying the proteins.