Development and application of fast NMR methods for the study of protein structure and dynamics

Multidimensional (nD) NMR is the method of choice for atom-resolved studies of protein structure and dynamics in solution. Among its current limitations are the long acquisition times required, translating to experimental times of several days or weeks for the set of experiments required for structural studies of proteins. Furthermore, real-time studies of kinetic processes occurring on a seconds time scale are inaccessible to standard nD NMR. This thesis is concerned with the development of fast nD NMR techniques based on longitudinal relaxation optimization. It is shown that 2D 1H-15N (3D 1H-15N-13C) correlation spectra can be obtained in only a few seconds (few minutes) of acquisition time for samples at millimolar concentration. In addition, the longitudinal relaxation optimized methods, when combined with alternative data sampling such as spatial or Hadamard encoding, can yield site-resolved 2D 1H-15N correlation spectra in acquisition times down to one second. Applications of fast 2D methods to the study of protein folding and unfolding are shown. This thesis also presents a longitudinal relaxation optimized method for the sensitivity-enhanced measurement of residual dipolar couplings between amide protons, as well as a fast and simple experiment for the characterization of protein samples, which can be very useful in the context of screening of sample conditions.