NMR at very low temperatures: An approach to millisecond-scale structure determination and micron-scale imaging

I will discuss two loosely-related projects, both involving nuclear magnetic resonance (NMR) and dynamic nuclear polarization (DNP) at temperatures below 30 K.  In the first project, we use rapid mixing and rapid freezing to trap transient intermediates in biochemical processes such as protein folding, ligand binding, and oligomerization, on time scales of several milliseconds.  The resulting frozen solutions are examined by DNP-enhanced magic-angle spinning NMR.  In the second  project, we use sensitivity gains from low temperatures and DNP, together with microcoil circuitry, to improve the spatial resolution of magnetic resonance imaging (MRI), with the goal of reaching isotropic resolution below one micron.  I will describe the technology we have developed for these projects, along with our most recent results.