A5048619779- Electron Spin Resonance Studies
- Advanced NMR Techniques and Applications
- Lanthanide and Transition Metal Complexes
- Solid-state spectroscopy and crystallography
- Magnetism in coordination complexes
- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Advanced MRI Techniques and Applications
- NMR spectroscopy and applications
- Atomic and Subatomic Physics Research
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- DNA and Nucleic Acid Chemistry
- Metal complexes synthesis and properties
- RNA and protein synthesis mechanisms
- Metalloenzymes and iron-sulfur proteins
- Photoreceptor and optogenetics research
- Electrochemical Analysis and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Porphyrin and Phthalocyanine Chemistry
- Analytical Chemistry and Sensors
- Enzyme Structure and Function
- Quantum, superfluid, helium dynamics
- Molecular Junctions and Nanostructures
Goethe University Frankfurt
2016-2025
Robert Bosch (Germany)
2019-2023
GP Batteries (China)
2020
Laboratoire de Chimie Moléculaire et Thioorganique
2020
Lithium Power (United States)
2020
Goethe Institute
2009-2018
Institute of Physical Chemistry
2016
McCormick (United States)
2015
University of Virginia
2015
University of Iceland
2014
A new polarizing agent with superior performance in dynamic nuclear polarization experiments is introduced, and utilizes two TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) moieties connected through a rigid spiro tether (see structure). The observed NMR signal intensities were enhanced by factor of 1.4 compared to those TOTAPOL, previously described TEMPO-based biradical flexible tether.
Distance distribution information obtained by pulsed dipolar EPR spectroscopy provides an important contribution to many studies in structural biology. Increasingly, such is used integrative modeling, where it delivers unique restraints on the width of conformational ensembles. In order ensure reliability models and biological conclusions, we herein define quality standards for sample preparation characterization, measurements distributed dipole-dipole couplings between paramagnetic labels,...
31P NMR revealed that the complex of p21ras with GTP analog GppNHp.Mg2+ exists in two conformational states, states 1 and 2. In wild-type equilibrium constant K1(12) between is 1.09. The population these different for various mutants but independent temperature. activation enthalpy delta H ++ entropy S transitions were determined by full-exchange matrix analysis p21ras(S65P). For protein one obtains = 89 +/- 2 kJ mol-1 102 20 J K-1 mutant 93 7 138 30 K-1. study suggests correspond to...
In a lot of cases active biomolecules are complexes higher order, thus methods capable counting the number building blocks and elucidating their geometric arrangement needed. Therefore, we experimentally validate here spin-counting via 4-pulse electron−electron double resonance (PELDOR) on well-defined test samples. Two biradicals, symmetric an asymmetric triradical, tetraradical were synthesized in convergent reaction scheme palladium-catalyzed cross-coupling reactions. PELDOR was then used...
A pulsed electron paramagnetic resonance (EPR) spectroscopic ruler for oligonucleotides was developed using a series of duplex DNAs. The spin-labeling is accomplished during solid-phase synthesis the utilizing palladium-catalyzed cross-coupling reaction between 5-iodo-2'-deoxyuridine and rigid spin-label 2,2,5,5-tetramethyl-pyrrolin-1-yloxyl-3-acetylene (TPA). 4-Pulse double (PELDOR) then used to measure intramolecular spin−spin distances via dipolar coupling, yielding 19.2, 23.3, 34.7,...
Abstract Show me your angle : Incorporation of the rigid spin label Ç allows determination both distance and orientation two nitroxide labels in DNA by PELDOR experiments at common X‐band frequencies. The orientational information is obtained varying position detection pulses over spectrum. Simulation set time traces yields very precise distances angles. magnified image
Mapping the structure of nucleic acids: Pulsed electron–electron double-resonance (PELDOR) spectroscopy has been applied for first time to map global acids inside Xenopus laevis oocytes (see picture). The distances measured in vitro and cells are same, which implies existence stable overall conformations hairpin RNA neomycin-sensing riboswitch studied. Detailed facts importance specialist readers published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or...
Electron paramagnetic resonance (EPR) spectroscopy is a powerful and widely used technique for studying structure dynamics of biomolecules under bio-orthogonal conditions. In-cell EPR an emerging area in this field; however, it hampered by the reducing environment present cells, which reduces most nitroxide spin labels to their corresponding diamagnetic N-hydroxyl derivatives. To determine radicals are best suited in-cell studies, we systematically studied effects substitution on radical...
Pulsed Electron-Electron Double Resonance (PELDOR) on double-stranded DNA (ds-DNA) was used to investigate the conformational flexibility of helical DNA. Stretching, twisting, and bending ds-DNA determined by incorporation two rigid nitroxide spin labels into a series 20 base pair (bp) duplexes. Orientation-selective PELDOR experiments performed at both X-band (9 GHz/0.3 T) G-band (180 GHz/6.4 with label distances in range 2-4 nm allowed us differentiate between different simple models...
Distance and spins: A new broadband, frequency-selective inversion pulse has been devised for pulsed electron–electron double resonance (PELDOR) spectroscopy, a unique method used to determine distance distributions between two or more paramagnetic centers 2–10 nm apart. The PELDOR modulation depth can be increased by substituting the rectangular pump shaped pulse. As service our authors readers, this journal provides supporting information supplied authors. Such materials are peer reviewed...
Abstract Membrane proteins may be influenced by the environment, and they unstable in detergents or fail to crystallize. As a result, approaches characterize structures native environment are highly desirable. Here, we report novel general strategy for precise distance measurements on outer membrane whole Escherichia coli cells isolated membranes. The cobalamin transporter BtuB was overexpressed spin‐labeled membranes interspin distances were measured using pulse EPR spectroscopy. A...
A high-frequency dynamic nuclear polarization (DNP)/electron paramagnetic resonance spectrometer operating at 211 MHz for1H and 140 GHz forg= 2 centers (5 T static field) is described. The salient feature of the instrument a cyclotron-resonance maser (gyrotron) which generates high-frequency, high-power microwave radiation. This gyrotron, under conventional operation produces millisecond pulses kilowatt powers, has been adapted to operate ∼100 W for 1 20 s in continuous wave mode 10 power...
Class I ribonucleotide reductases (RNRs) are composed of two subunits, R1 and R2. The R2 subunit contains the essential diferric cluster-tyrosyl radical (Y.) cofactor, is site conversion nucleoside diphosphates to 2'-deoxynucleoside diphosphates. It has been proposed that function tyrosyl in generate a transient thiyl (C439.) over distance 35 A, which turn initiates reduction process. EPR measurements provide tool with study mechanism initiation class RNRs. These types experiments at low...
Cytochrome c oxidase (COX) catalyzes the reduction of oxygen to water, a process which is accompanied by pumping four protons across membrane. Elucidation structures intermediates in these processes crucial for understanding mechanism reduction. In work presented here, reaction H2O2 with fully oxidized protein at pH 6.0 has been investigated electron paramagnetic resonance (EPR) spectroscopy. The results reveal an EPR signal partially resolved hyperfine structure typical organic radical....
To facilitate the measurement of intramolecular distances in solvated RNA systems, a combination spin-labeling, electron paramagnetic resonance (EPR), and molecular dynamics (MD) simulation is presented. The fairly rigid spin label 2,2,5,5-tetramethyl-pyrrolin-1-yloxyl-3-acetylene (TPA) was base site specifically introduced into through Sonogashira palladium catalyzed cross-coupling on column. For this purpose 5-iodo-uridine, 5-iodo-cytidine 2-iodo-adenosine phosphoramidites were synthesized...
Metal ions are functionally or structurally important centers in metalloproteins RNAs, which makes them interesting targets for spectroscopic investigations. In combination with site-directed spin labeling, pulsed electron−electron double resonance (PELDOR DEER) could be a well-suited method to characterize and localize them. Here, we report on the synthesis, full characterization, PELDOR study of copper(II) porphyrin/nitroxide model system. The X-band time traces contain besides distance...