AbstractsBiology & Animal Science

Nuclear magnetic resonance is a robust tool in a broad range of scientific area from biochemistry, material science to MRI in medical application. In this thesis, two distinct works are presented in both solid sate and liquid state NMR. Firstly, benefiting from the fast MAS and cleverly designed devices, both resolution and sensitivity of solid state NMR spectra have been improved many folds, so that it is available to study complex biological solids, such as proteins. However there is always a need to increase resolution in order to work on more complicate systems. Here, we introduce a series of highly resolved scalar-based three-dimensional homonuclear correlation experiments for 13C sidechain correlation in solid-state proteins. These experiments are based on a sensitive constant-time format, in which homonuclear scalar couplings are utilized for polarization transfer, but decoupled during chemical shift evolution, to yield high resolution in indirect dimensions and band selectivity as desired. Together with the experiments designed to obtain backbone correlations, we could fully assign the backbone and aliphatic sidechain chemical shifts with the 3D spectra that are collected on 9.4T magnet (1H frequency 400MHz) for model protein GB1. We also discuss the method of chemical shift based structural refinement. Another practice of NMR in my work is using 31P Dynamic NMR to characterize the backbone conformation and dynamics in DNA Dickerson Dodecamer. The results confirm solid-state 2H-NMR experiments showing that the C3pG4 and C9pG10 steps experience unique dynamics. And cytosine methylation has significant impact on the local dynamics. The results also show that 31P Dynamic NMR is an efficient way to extract DNA backbone dynamic information, and provide detail knowledge to study DNA-protein interactions.