Regensburg 2010 – wissenschaftliches Programm

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TUT: Tutorials

TUT 2: Tutorial: Physics of NMR - Physics with NMR

TUT 2.3: Tutorium

Sonntag, 21. März 2010, 17:45–18:30, H3

NMR at High Pressures and High Fields — •Hans Robert Kalbitzer — Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany

The two main methods for biomolecular structure determination are X-ray crystallography and NMR spectroscopy. The major advantage of the former is that virtually no size limit exists for the investigated macromolecules. Yet, only well crystallizeable systems can be analyzed preventing the investigation of for example transient complexes. NMR has the benefit that analysis can be performed in solution under nearly physiological conditions and dynamics can be studied in detail. High pressure NMR has developed in the last decade to a valuable tool for studying biophysical properties of proteins. Static pressure up to 400 MPa is applied to the sample located inside the high-field NMR spectrometer. The pressure is transferred to the sample cell via a pressurizing fluid and can be changed during the experiments. Besides an anisotropic compression of the protein, the most important feature of high pressure NMR spectroscopy is that conformational equilibria can be shifted reversibly, allowing the detection and structural characterization of excited states that are only weakly populated at ambient pressure. Time-dependent non-equilibrium states can be detected by pressure-jump NMR spectroscopy where the pressure is changed repeatedly by approximately 100 MPa in a time scale of 30 ms inside the NMR spectrometer. The pressure response is correlated to NMR parameters by introducing the pressure jumps in a complex pulse sequence (pressure correlation spectroscopy).