A combination of novel solid-state NMR methods and related software to study molecular assemblies and biomolecules

Abstract

Solid-state Nuclear Magnetic Resonance (ssNMR) is a versatile spectroscopic method that can be applied to various samples relevant in life and material science and provides atomic insight into molecular structure, dynamics and assembly. The present thesis describes the diversity and utility of ssNMR studies in different contexts. The potential of ssNMR to determine molecular structure is illustrated by means of a homopolymeric protein hydrogel with sequence similarities to the scNsp1p nucleoporin of the Nuclear Pore Complex. Chemical shift assignments and distance restraints that were derived from a range of ssNMR measurements permitted to build a first structural model. In addition, ssNMR is a powerful tool to investigate dynamical features of molecular systems by probing different motional regimes. Special tailored ssNMR experiments, which monitor selectively either rigid or mobile protein segments, revealed significant dynamical changes of the Nup98 FG nucleoporin hydrogel in comparison with its O-GlcNAc modified version. Furthermore, ssNMR allows to follow time-resolved processes like self-assembly or chemical exchange. This is shown for the micelle formation of the thermosensitive, amphiphilic copolymer mPEG-b-p(HPMAm-Nt18-co-HPMAm-Lac82). SsNMR measurements above and below its critical micelle temperature allowed to identify the leading interaction involved in the formation. Finally, all these applications are supported and further enhanced by constant new developments in the field of ssNMR methodology as e.g. dedicated software routines. One chapter of the thesis deals with the novel software environment and web portal FANDAS (Fast Analysis of multidimensional NMR DAta Sets) which facilitates ssNMR data analysis of biomolecular spectra and allows to estimate the efficiency of NMR experiments and sample labeling schemes beforehand. Further developments in the field of ssNMR include advanced sample preparation that is often combined with novel NMR methods. In this context, the thesis discusses the potential of perdeuteration in combination with ultra-fast magic angle spinning via studying the membrane protein Sensory Rhodopsin II in its lipid environment in order to obtain additional structural information.