DEVELOPING CHEMICAL EXCHANGE SATURATION TRANSFER (CEST) BASED NMR TECHNIQUES TO STUDY PROTEIN DYNAMICS

ZHOU YANG

Publication

DEVELOPING CHEMICAL EXCHANGE SATURATION TRANSFER (CEST) BASED NMR TECHNIQUES TO STUDY PROTEIN DYNAMICS

ZHOU YANG

Abstract

An approximation method of considering J-coupling effects on chemical exchange saturation transfer (CEST) NMR experiments and the studies on folding of two proteins by CEST methods are presented in the thesis. The J-coupling approximation method was constructed upon a theoretical derivation, examined by simulations and supported by 13CO and 15N CEST experiments on meACP, a protein undergoing a folding/unfolding exchange process. Furthermore, CEST experiments on meACP folding demonstrated a partially unfolded intermediate state, whose N-terminal region is unfolded while the C-terminal region is folded, as well as a native-like transition state. Finally, CEST and relaxation dispersion experiments on the repetitive domain from minor ampullate spider silk protein (RPmi) showed that there exists a fast exchange process (~3900 s-1) between the native state and possibly an unfolded state in the system. Overall, the thesis demonstrates an improvement of CEST methods by considering J-coupling effects and CEST applications in studying protein folding, the mechanism of which remains missing.