Triggered functional dynamics of proteins in biomimetic environments by time-resolved electron paramagnetic resonance at very high magnetic fields

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Proteins are the nano-scopic molecular machines that power life as we know it. Thanks to a revolution in structural biology, we now know the three-dimensional shapes of more than 150,000 proteins. However, to fully understand the operation of proteins as machines, one must understand how they move after being triggered by an external event such as attaching to a particular molecule, movement of a neighboring protein, or a change in voltage or light intensity. A particularly exciting class of proteins called photo responsive proteins can move to control the behaviors of cells when exposed to light. This research will develop an advanced form of magnetic resonance—of which the most familiar application is magnetic resonance imaging (MRI)—to make “movies” of the motion of photo responsive proteins in response to a flash of light. The ability to “film” protein motion will provide critical tools to guide widespread efforts to engineer and optimize proteins for important applications ranging from sustainable manufacturing to controlling nerves with light. This project will engage next generation of scientists by public outreach activities through the “Questboard” developed by the PI’s group. Proteins are the molecular machines that power life as we know it. The rapidly-growing protein data bank now holds more than 150,000 protein structures. However, to fully understand the operation of proteins as machines, one must understand their triggered functional dynamics--how protein structures evolve in time after being triggered by an external event such as ligand docking, movement of a neighboring protein, or a change in voltage or light intensity. Photo responsive proteins are a particularly exciting class of proteins that, after absorbing a photon, generate mechanical energy to modulate biochemical processes and cellular behavior. This project will support convergent research to measure the time-resolved conformational changes triggered by a pulse of light in two photo responsive proteins: a microbial rhodopsin proton pump, and optogenetic proteins called Light, Oxygen, and Voltage (LOV) sensing domains. The measurements are enabled by a unique methodology, under development over the last decade by the PI and co-PI, which combines electron paramagnetic resonance (EPR) at very high magnetic fields (8.6 Tesla) and frequencies (240 GHz) with site-directed mutagenesis and spin labeling using compounds based on Gd (III) paramagnetic metal centers. This project is supported by the Molecular Biophysics Cluster of the Molecular and Cellular Biosciences Division in the Biological Sciences Directorate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.