Long lived states in high field NMR spectroscopy for the study of very slow dynamic processes in solution state

In solution-state NMR spectroscopy, dynamic processes can be probed provided the nuclear relaxation rate constant does not exceed the rate constant of the process. Phenomena occurring on a time scale longer than the spin-lattice relaxation time constant, T1, were not amenable to study by conventional NMR. The discovery of long-lived nuclear spin states (LLS) in 2004, by M. Levitt, M. Carravetta and O. W. Johannessen, showed that lifetimes of magnetization can be much higher than T1. LLS experiments can be performed either in zero or in high magnetic fields for scalar-coupled proton spin pairs. This thesis contributes methods for exciting and preserving LLS in high field for a wide class of molecules, including sugars, amino acids and nucleotides. Slow diffusion has been measured for a mixture of molecules having different NMR parameters using LLS. Conformational exchange could also be followed by exchange spectroscopy in BPTI. Recently, LLS have been observed in highly mobile parts (Gly-75 and 76) of Ubiquitin. Dynamic Nuclear Polarization (DNP) is one of the methods to overcome the inherent low sensitivity of NMR spectroscopy. We have conceived an experiment to preserve DNP enhanced magnetization by conversion into LLS. A way of improving resolution and sensitivity of NMR has been designed by creation of long-lived coherences (LLC) in biomolecules.