Applications of advanced solid-state NMR methods for probing intermolecular interactions, notably hydrogen bonding are presented: Homonuclear 1H-1H double-quantum (DQ) experiments reveal proximities (typically under 3.5 Angstroms) among pairs of hydrogen atoms, for example distinguishing between ribbon-like or quartet-like self assembly in guanosine supramolecular structures [1-2] or pushing...
The difficulty to automate data acquisition and analysis of complex protein spectra has been one of the major bottlenecks for the widespread use of NMR spectroscopy in structural biology. A promising approach are spectra of high dimensionality (>3) which yield multiple nuclear correlations within fewer experiments, provide high resolution and unambigouos sequential resonance assignment, thus...
Solid-state NMR is a very flexible and powerful technique for the elucidation of geometry and dynamics information on a variety of samples. However, there is still a need to overcome sensitivity and resolution aspects along with the necessity to carry out multidimensional experiments in a short span of time. In order to overcome these challenges, we have made use of two approaches.
First...
Spin-diffusion (SD) was amongst the first methods proposed to spatially transfer polarization between dipolar-coupled nuclear spins. Lab-frame proton spin-diffusion (PSD) has proved particularly useful in structural characterization of a large variety of molecules. Perturbation theory treatment of the SD phenomenon states that during SD, the rate constant of magnetization exchange between two...
We have developed experimental methods for initiating nonequilibrium structural conversion processes (e.g., protein folding, peptide self-assembly, ligand/receptor complex formation, etc.) by rapid mixing and for trapping intermediate states by rapid freezing after a defined time interval, on the millisecond time scale. When combined with low-temperature dynamic nuclear polarization,...