Protein Dynamics and Monomer−Monomer Interactions in AntR Activation by Electron Paramagnetic Resonance and Double Electron−Electron Resonance†

Biochemistry ◽  
2007 ◽  
Vol 46 (41) ◽  
pp. 11639-11649 ◽  
Author(s):  
K. Ilker Sen ◽  
Timothy M. Logan ◽  
Piotr G. Fajer
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Protein Dynamics ◽  
Paramagnetic Resonance ◽  
Electron Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance ◽  
Electron Paramagnetic

Dipolar pathways in dipolar EPR spectroscopy

2022 ◽  
Author(s):  
Luis Fábregas-Ibáñez ◽  
Maxx H. Tessmer ◽  
Gunnar Jeschke ◽  
Stefan Stoll
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Structural Characterization ◽  
Epr Spectroscopy ◽  
Nanometer Scale ◽  
Paramagnetic Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance ◽  
Electron Paramagnetic ◽  
Epr Experiments

Dipolar electron paramagnetic resonance (EPR) experiments such as double electron--electron resonance (DEER) measure distributions of nanometer-scale distances between unpaired electrons, which provide valuable information for structural characterization of proteins and...

scholarly journals The contribution of modern EPR to structural biology

2018 ◽  
Vol 2 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Gunnar Jeschke
Keyword(s):  
System Size ◽  
Native Conformation ◽  
Paramagnetic Resonance ◽  
Building Models ◽  
Distance Distributions ◽  
Double Electron ◽  
The Mean ◽  
Structural Restraints ◽  
Double Electron Electron Resonance ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) spectroscopy combined with site-directed spin labelling is applicable to biomolecules and their complexes irrespective of system size and in a broad range of environments. Neither short-range nor long-range order is required to obtain structural restraints on accessibility of sites to water or oxygen, on secondary structure, and on distances between sites. Many of the experiments characterize a static ensemble obtained by shock-freezing. Compared with characterizing the dynamic ensemble at ambient temperature, analysis is simplified and information loss due to overlapping timescales of measurement and system dynamics is avoided. The necessity for labelling leads to sparse restraint sets that require integration with data from other methodologies for building models. The double electron–electron resonance experiment provides distance distributions in the nanometre range that carry information not only on the mean conformation but also on the width of the native ensemble. The distribution widths are often inconsistent with Anfinsen's concept that a sequence encodes a single native conformation defined at atomic resolution under physiological conditions.

scholarly journals Characterization of Aqueous Lower Polarity Solvation Shells Around Amphiphilic TEMPO Radicals in Water

2020 ◽  
Author(s):  
Johannes Hunold ◽  
Jana Eisermann ◽  
Martin Brehm ◽  
Dariush Hinderberger
Keyword(s):  
Organic Solvents ◽  
Pure Water ◽  
Paramagnetic Resonance ◽  
Double Electron ◽  
Spectral Simulations ◽  
Local Enrichment ◽  
Double Electron Electron Resonance ◽  
Electron Paramagnetic ◽  
Stable Nitroxide

Solvation of the stable nitroxide radicals 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) and 4-Oxo-TEMPO (TEMPONE) in water and THF is studied. With electron paramagnetic resonance (EPR) spectroscopy at X- and Q-band as well as spectral simulations, the existence of pure water shells enclosing TEMPO in aqueous solution that lead to significantly reduced local polarity at the nitroxide is shown. These aqueous lower polarity solvation shells (ALPSS) offer TEMPO a local polarity that is similar to that in organic solvents like THF. Furthermore, using double electron-electron resonance (DEER) spectroscopy, local enrichment and inhomogenous distribution without collisions of dissolved TEMPO in water is found that can be correlated with potentially attractive interactions mediated through ALPSS. However, no local enrichment of TEMPO is found in organic solvents such as THF. These results are substantiated by MD and metadynamics simulations and physical methods like DLS and MS.

Characterization of Aqueous Lower Polarity Solvation Shells Around Amphiphilic TEMPO Radicals in Water

2020 ◽  
Author(s):  
Johannes Hunold ◽  
Jana Eisermann ◽  
Martin Brehm ◽  
Dariush Hinderberger
Keyword(s):  
Organic Solvents ◽  
Pure Water ◽  
Paramagnetic Resonance ◽  
Double Electron ◽  
Spectral Simulations ◽  
Local Enrichment ◽  
Double Electron Electron Resonance ◽  
Electron Paramagnetic ◽  
Stable Nitroxide

Solvation of the stable nitroxide radicals 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) and 4-Oxo-TEMPO (TEMPONE) in water and THF is studied. With electron paramagnetic resonance (EPR) spectroscopy at X- and Q-band as well as spectral simulations, the existence of pure water shells enclosing TEMPO in aqueous solution that lead to significantly reduced local polarity at the nitroxide is shown. These aqueous lower polarity solvation shells (ALPSS) offer TEMPO a local polarity that is similar to that in organic solvents like THF. Furthermore, using double electron-electron resonance (DEER) spectroscopy, local enrichment and inhomogenous distribution without collisions of dissolved TEMPO in water is found that can be correlated with potentially attractive interactions mediated through ALPSS. However, no local enrichment of TEMPO is found in organic solvents such as THF. These results are substantiated by MD and metadynamics simulations and physical methods like DLS and MS.

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