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Seminar by Dr. Björn Corzilius (Solid State Dynamic Nuclear Polarization, Göttingen) (Lecture)

Friday 13 January 2017Add to my calendar
from 11:30
Dr. Björn Corzilius (Solid State Dynamic Nuclear Polarization, Göttingen)

Bjorn Corzilius jan2017Nuclear Magnetic Resonance (NMR) is a powerful and indispensable technique in structural biology. For large biomolecular systems, including protein complexes and nucleic acids as well as whole cellular organelles, magic-angle spinning NMR has proven extremely valuable for the determination of atomistic structures if other methods such as X-ray crystallography are not applicable. Nevertheless, the inherently low sensitivity of the nuclear spins is still one of the limiting factors in its application. Dynamic nuclear polarization (DNP) has been introduced as a tool to overcome this problem by transferring the significantly larger spin polarization of unpaired electrons to the nuclei of interest during a typical NMR experiment.
For DNP, electron spins have to be present as polarizing agents. This can be achieved by adding paramagnetic species to the (diamagnetic) sample. Besides the typical nitroxide-based persistent radicals, paramagnetic metal complexes of Mn(II) and Gd(III) are of particular interest due to their electron paramagnetic resonance (EPR) spectral properties and possibility to be incorporated within biomolecules.[1, 2]
We show that endogenous paramagnetic ions within biomolecules or doped materials can be used for intramolecular DNP. We present several examples of paramagnetic biomolecules, including proteins and ribonucleic acids and demonstrate the successful polarization transfer between the paramagnetic moiety and the nuclei of interest.[3, 4] We discuss the prospect of site-specific, direct nuclear polarization by endogenous paramagnetic sites which could be used for the generation of distance constraints in structural biology, and demonstrate the novel utilization of heteronuclear cross-relaxation for selective probing of contact surfaces specifically under DNP.[5]
[1] B. Corzilius, A.A. Smith, A.B. Barnes, C. Luchinat, I. Bertini, R.G. Griffin, High-Field Dynamic Nuclear Polarization with High-Spin Transition Metal Ions, J. Am. Chem. Soc., 133 (2011) 5648-5651.
[2] B. Corzilius, Theory of solid effect and cross effect dynamic nuclear polarization with half-integer high-spin metal polarizing agents in rotating solids, Phys. Chem. Chem. Phys., 18 (2016) 27190-27204.
[3] P. Wenk, M. Kaushik, D. Richter, M. Vogel, B. Suess, B. Corzilius, Dynamic nuclear polarization of nucleic acid with endogenously bound manganese, J. Biomol. NMR, 63 (2015) 97-109.
[4] M. Kaushik, T. Bahrenberg, T.V. Can, M.A. Caporini, R. Silvers, J. Heiliger, A.A. Smith, H. Schwalbe, R.G. Griffin, B. Corzilius, Gd(III) and Mn(II) complexes for dynamic nuclear polarization: small molecular chelate polarizing agents and applications with site-directed spin labeling of proteins, Phys. Chem. Chem. Phys., 18 (2016) 27205-27218.
[5] D. Daube, V. Aladin, J. Heiliger, J. Wittmann, D. Barthelmes, C. Bengs, H. Schwalbe, B. Corzilius, Heteronuclear cross-relaxation under solid-state dynamic nuclear polarization, J. Am. Chem. Soc., doi:10.1021/jacs.6b08683 (2016).

prof. Arno Kentgens