Neue Liganden die sowohl für FRET-Spektroscopy als auch für DEER EPR-Messungen und PCS-NMR Experimente dienen können sollen synthetisiert und optimiert werden.

Over the last decades, NMR spectroscopy has dramatically changed research in the molecular sciences. The frontiers of NMR spectroscopy are pushed forward by new developments in instrumentation, among others. In particular, new instruments have become available that drastically increase the sensitivity with regard to sample limited scientific problems, or for 19F spectroscopy of e.g. complex biomolecules or nanoparticles. This R'Equip project proposal requests the purchase of a 600 MHz NMR spectrometer, equipped with a cryoplatform and two cryoprobes, a 1.7 mm TCI cyroprobe and a 5 mm QCI-F quadruple cryoprobe for fluorine applications. The requested NMR spectrometer will facilitate research in two major directions: (1) research questions where only a limited amount of sample is available and (2) studies that require a high amount of 19F sensitivity. For the first research area, the requested instrument enables full structural characterization of small molecules on the nanogram scale. For the second line of investigation, the requested instrument allows to cut measurement time by a factor of 80-100, with an identical signal to noise ratio. Therefore, this significant increase in sensitivity will allow addressing problems that have so far escaped scientific research.  The requested instrument will enable research in a variety of scientific disciplines, such as chemistry, chemical biology, pharmacy, pharmacology, molecular toxicology, biochemistry, enzymology, structural biology and nanoscience, among others. Six research groups from several departments at the University of Basel (Chemistry, Biozentrum, Pharmaceutical Science, Swiss Center of Applied Human Toxicology and the Swiss Nanoscience Institute) take part in this application, underlining the broad usage potential of the requested instrument by many disciplines in the molecular sciences. It is envisioned that other research groups from Switzerland from the above disciplines and beyond will utilize this instrument as well. Over the last decades, NMR spectroscopy has dramatically changed research in the molecular sciences. The frontiers of NMR spectroscopy are pushed forward by new developments in instrumentation, among others. In particular, new instruments have become available that drastically increase the sensitivity with regard to sample limited scientific problems, or for 19F spectroscopy of e.g. complex biomolecules or nanoparticles. This R'Equip project proposal requests the purchase of a 600 MHz NMR spectrometer, equipped with a cryoplatform and two cryoprobes, a 1.7 mm TCI cyroprobe and a 5 mm QCI-F quadruple cryoprobe for fluorine applications. The requested NMR spectrometer will facilitate research in two major directions: (1) research questions where only a limited amount of sample is available and (2) studies that require a high amount of 19F sensitivity. For the first research area, the requested instrument enables full structural characterization of small molecules on the nanogram scale. For the second line of investigation, the requested instrument allows to cut measurement time by a factor of 80-100, with an identical signal to noise ratio. Therefore, this significant increase in sensitivity will allow addressing problems that have so far escaped scientific research.The requested instrument will enable research in a variety of scientific disciplines, such as chemistry, chemical biology, pharmacy, pharmacology, molecular toxicology, biochemistry, enzymology, structural biology and nanoscience, among others. Six research groups from several departments at the University of Basel (Chemistry, Biozentrum, Pharmaceutical Science, Swiss Center of Applied Human Toxicology and the Swiss Nanoscience Institute) take part in this application, underlining the broad usage potential of the requested instrument by many disciplines in the molecular sciences. It is envisioned that other research groups from Switzerland from the above disciplines and beyond will utilize this instrument as well.

Determination of the three-dimensional structure of proteins in solution is a stronghold of modern bio-molecular NMR spectroscopy. Even more important for understanding processes in the living cell is the characterization of interaction sites and surfaces of protein-protein and protein-ligand complexes. NMR can provide not only structural but also dynamic information on this subject. Pseudo contact shift (PCS) NMR spectroscopy has a unique property as it is a long-range method that can cover distances of more than 50 Å, in combination with precise angle information. The very sensitive 2D-NMR experiments can be performed even on larger proteins, provided a state of the art spectrometer is available. We have recently presented a new lanthanide chelating tag "M8", based on a sterically overcrowded DOTA framework that shows PCS of unprecedented size when linked to ubiquitin. This project is aimed at further improving the properties of the new ligand by systematically optimizing the linker between the DOTA core and the protein and by variation of the donor atom set of the chelator.

Determination of the three-dimensional structure of proteins in solution is a stronghold of modern bio-molecular NMR spectroscopy. Even more important for understanding processes in the living cell is the characterization of interaction sites and surfaces of protein-protein and protein-ligand complexes. NMR can provide not only structural but also dynamic information on this subject. Classical determination of NOE distant restraints has recently been complemented by techniques, which utilize paramagnetic lanthanide ions that are tagged covalently to the suitably modified protein. Besides residual dipolar couplings (RDCs) and paramagnetic relaxation enhancement (PRE) the focus of this proposal is aimed at pseudo contact shift (PCS) NMR spectroscopy. PCS NMR has unique properties as it is a long-range method that can cover distances of more than 50 Å, in combination with precise angle information. The very sensitive measurements are simple 2D-NMR experiments that can be performed even on larger proteins. We have recently presented a new lanthanide chelating tag "M8", based on a sterically overcrowded DOTA framework that shows PCS of unprecedented size when linked to ubiquitin. This project is aimed at further improving the properties of the new ligand by systematically fine-tuning the type and the rigidity of the linker between the DOTA core and the protein. In a second step, variation of the donor atoms of the chelator should trigger a strong crystal field distortion for the lanthanide ion and might result in a more pronounced anisotropy of the susceptibility tensor and hence stronger PCS. Finally a screening of at least a number of different lanthanides should yield, together with the variation of the first two parameters, a family of lanthanide chelating tags that should be suitable for tackling a variety of different problems in structural biology. As the stereospecific synthesis of the macrocyclic ligand is tedious and demanding, a number of interesting collaborations with other groups is already underway or is planned for the near future. We will therefore have a chance to study the individual benefits of the various members of our LCT family by applying them to a number of challenging bio-molecular questions.