Emerging Experimental Probes For The Spatial And Temporal Resolution Of Protein Dynamics In Enzyme Catalysis

Macromolecular dynamics is an integral part of our understanding of protein function. This talk will focus on temperature dependent hydrogen deuterium exchange by mass spectrometry (TDHDX-MS) as a tool to uncover spatially resolved thermal networks that connect protein/solvent interfaces to reaction centers. When TDHDX-MS is combined with time and temperature dependent Stokes shifts measurements, experimental evidence emerges for site-specific protein quakes as the source of the thermal activation of active site chemistry. A background of equilibrium sampling among a wide range of protein sub-states acts in concert with protein quakes, to enable precise positioning of active site components with regard to their anisotropic thermal conduits. This behavior provides a unifying model for both enzymatic catalytic rate enhancement and allosteric regulation. Supported by NIGMS.