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Applications
Photo-ejected ligands hyperpolarized by parahydrogen in reversible exchange
Emily E. Brown, Rielly J. Harrison, Dmytro Havrylyuk, Stephen J. McBride, Edith C. Glazer, Felix N. Castellano and Thomas Theis
Chem. Commun., 2025,61, 4674-4677
Hyperpolarization derived from signal amplification by reversible exchange (SABRE) is valued for its relative simplicity among hyperpolarization approaches. Here, we demonstrate that photoejection of the ligands pyridazine and pyrazine from prodrug Ru(II) polypyridyl complexes offers a new modality for activating SABRE hyperpolarization, achieving enhancements of over 3200-fold.
Amber Light Control of Peptide Secondary Structure by a Perfluoroaromatic Azobenzene Photoswitch
E. Cataldi, M. Raschig, M. Gutmann, P. T. Geppert, M. Ruopp, M. Schock, H. Gerwe, R. Bertermann, L. Meinel, M. Finze, A. Nowak-Król, M. Decker, T. Lühmann
ChemBioChem 2023, 24, e202200570.
When amber means “go”: A perfluorinated azobenzene was synthesized and stapled to free cysteines within a helical peptide by using site-selective perfluoroarylation chemistry. Illumination experiments proved successful change of the peptide's secondary structure in response to amber light.
Contrast Agents Based on Human Serum Albumin and Nitroxides for 1H-MRI and Overhauser-Enhanced MRI
Mitin, Dmitry; Bullinger, Friedemann; Dobrynin, Sergey; Engelmann, Joern; Scheffler, Klaus; et al.
Int. J. Mol. Sci. 2024, 25(7), 4041
In cancer diagnostics, magnetic resonance imaging (MRI) uses contrast agents to enhance the distinction between the target tissue and background. Several promising approaches have been developed to increase MRI sensitivity, one of which ...
LC-Photo-CIDNP hyperpolarization of biomolecules bearing a quasi-isolated spin pair: Magnetic-Field dependence via a rapid-shuttling device
- Optically enhanced NMR and ultra-rapid field cycling generate high hyperpolarization in liquids.
- Up/down shuttle occurs within 90–120 ms, yields Lorentzian lineshapes and minimal T1 distortions.
- Our approach is most effective fort biomolecules carrying a quasi-isolated spin pair (QISP)
- 1,200-fold S/N enhancement is achieved at 1 mM) sample concentration at 1.18 T illumination field.
Biomolecular Dynamics
Within applications of relaxometry, protein applications require the most high resolution and sensitivity. Due to the value range of relaxation parameters of biomolecular systems, in addition to the demand for high resolution, a rapid field switch is essential.
High Resolution 31P Field Cycling NMR Reveals Unsuspected Features of Enzyme-Substrate-Cofactor Dynamics
Mary F. Roberts and Lizbeth Hedstrom
Front. Mol. Biosci. 9:865519.
The dynamic interactions of enzymes and substrates underpins catalysis, yet few techniques can interrogate the dynamics of protein-bound ligands. Here we describe the use of field cycling NMR relaxometry to measure the dynamics of enzyme-bound substrates and cofactors in catalytically competent complexes of GMP reductase. These studies reveal new binding modes unanticipated by x-ray crystal structures and reaction-specific dynamic networks. Importantly, this work demonstrates that distal interactions not usually considered part of the reaction coordinate can play an active role in catalysis. The commercialization of shuttling apparatus will make field cycling relaxometry more accessible and expand its use to additional nuclei, promising more intriguing findings to come.
Relaxivity on Contrast Agents
In addition to protein dynamics investigation, relaxivity measurement on contrast agents is also a hot topic in NMR relaxometry studies. Relaxivity measurement is also a field-dependent relaxation measurement but observing on the solvent side. Its important application as contrast agents in MRI. The agents perturb the relaxation mechanism in water to increase the imaging contrast in the region of interest.
Environmental Science
In the field of soil chemistry and environmental chemistry, field-cycling NMR relaxometry has not yet been a well-recognized approach. Hence, Prof. Conte has shared two of his works to introduce the capability of field-cycling NMR in applications of soil chemistry and environmental chemistry. For scientists who are interested in environmental science, relaxometry can explore more and open different windows of molecular dynamics in soil chemistry.
Material Science
Ever since the early days of field-cycling NMR, the dynamics of molecules in the liquid or the solid state have been at the center of interest; even more, combination of both phases such as the motion of molecules on solid surfaces ask for the versatility of measuring the longitudinal relaxation time as a function of magnetic field strength. “Molecular dynamics” in this sense covers two different aspects: the statistics of rotational and translational motion of small molecules that are assumed as rigid, and the consequences of internal motion on the overall mobility in larger molecules such as polymers.
NUCLEAR SPIN-HYPERPOLARIZATION GENERATED IN A FLAVOPROTEIN UNDER ILLUMINATION: EXPERIMENTAL FIELD-DEPENDENCE AND THEORETICAL LEVEL CROSSING ANALYSIS
Yonghong Ding, Alexey S. Kiryutin, Alexandra V. Yurkovskaya, Denis V. Sosnovsky, Renad Z. Sagdeev, Saskia Bannister, Tilman Kottke, Rajiv K. Kar, Igor Schapiro, Konstantin L. Ivanov & Joerg Matysik
Scientific Reports 9, 18436 (2019)
Field-Cycling on Photo-CIDNP
CIDNP (Chemical Induced Dynamic Nuclear Polarization) is a high-sensitivity method for photochemical reactions investigation and radical studies. This manner is also able to apply to protein dynamics investigation, such as protein folding. Studies of CIDNP in weak magnetic fields even give additional information on radical reaction mechanisms and on exchange processes.
Studies of low magnetic field photo-CIDNP require two mechanical breakthroughs, one is a lumination unit, the other is a switcher of magnetic fields. The Lumination unit was developed by using a specific wavelength laser and a light guide to the NMR tube. Nowadays, the lumination unit was alternatively performed by Light-emission diodes (LED) instead of laser lumination. As for the switcher of magnetic fields, one can imply field-cycler to carry the sample to the low-field where the lumination unit is located.
Circularly permuted LOV2 as a modular photoswitch for optogenetic engineering
He, L., Tan, P., Zhu, L. et al.
Nat Chem Biol 17, 915–923 (2021).
Ultrafast Fragment Screening Using Photo-Hyperpolarized (CIDNP) NMR
Felix Torres, Matthias Bütikofer, Gabriela R. Stadler, Alois Renn, Harindranath Kadavath, Raitis Bobrovs, Kristaps Jaudzems, and Roland Riek
Journal of the American Chemical Society 2023 145 (22), 12066-12080
Time-resolved NMR studies of RNA folding
Boris Fürtig, Janina Buck, Vijayalaxmi Manoharan, Wolfgang Bermel, Andres Jäschke, Philipp Wenter, Stefan Pitsch, and Harald Schwalbe
Biopolymers Volume86, Issue5-6, Special Issue: Special Focus on NMR of Nucleic Acids, 5 – 15 August 2007, Pages 360-383
.... information derived from time-resolved NMR experiments, namely the acquisition of native chemical shifts, can be readily interpreted in light of formation of a single long-range hydrogen bonding interaction. Together with mutational data that can readily be obtained for RNA and new ligation technologies that enhance site resolution even further, time-resolved NMR may become a powerful tool to decipher RNA folding. ...
Exploration of the close chemical space of tryptophan and tyrosine reveals importance of hydrophobicity in CW-photo-CIDNP performances
Felix Torres, Alois Renn, and Roland Riek
Magn. Reson., 2, 321–329, https://doi.org/10.5194/mr-2-321-2021, 2021.
.... In photo-CIDNP of interest here the radical pair is between a dye and the molecule to be polarized. Here, we explore continuous-wave (CW) photo-CIDNP (denoted CW-photo-CIDNP) with a set of 10 tryptophan and tyrosine analogues, many of them newly identified to be photo-CIDNP active, and we observe not only signal enhancement of 2 orders of magnitude for 1H at 600 MHz (corresponding to 10 000 times in measurement time) but also reveal that polarization enhancement correlates with the hydrophobicity of the molecules. Furthermore, the small chemical library established indicates the existence of many photo-CIDNP-active molecules.
Pulse-Programmable Magnetic Field Cycling of Parahydrogen-Induced Polarization by Side Arm Hydrogenation
Baptiste Joalland, et al.
Anal Chem. 2020 Jan 7;92(1):1340-1345.
Pulse-Effects of Magnetic Field Cycle on the Polarization Transfer from Parahydrogen to Heteronuclei through Long-Range J-Couplings
Eleonora Cavallari, Carla Carrera, Tommaso Boi, Silvio Aime, and Francesca Reineri
J. Phys. Chem. B 2015, 119, 31, 10035–10041
Fast-field-cycling ultralow-field nuclear magnetic relaxation dispersion
Bodenstedt, S., Mitchell, M.W. & Tayler, M.C.D.
Nat. Commun. 12, 4041 (2021).