Journal: Applied Magnetic Resonance

Abbreviation

Appl. Magn. Reson.

Publisher

Springer

Journal Volumes

ISSN

0937-9347
1613-7507

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Publications 1 - 10 of 19
  • Two-Dimensional Distance Correlation Maps from Pulsed Triple Electron Resonance (TRIER) on Proteins with Three Paramagnetic Centers
    Item type: Journal Article
    Pribitzer, Stephan; Ibáñez, Luis F.; Gmeiner, Christoph; et al. (2018)
    Applied Magnetic Resonance
    Recently, we introduced the pulsed triple electron resonance (TRIER) experiment, which correlates dipolar frequencies of molecules with three electron spins. These correlation patterns contain valuable information: in combination with double electron–electron resonance (DEER) they allow to interpret distance distributions of biological systems that exist in more than one conformation. Together with an improved sequence and new data processing, we were now for the first time able to obtain two-dimensional distance correlation maps of the previously investigated model compounds as well as of spin-labeled proteins. For this we applied two-dimensional approximate Pake transformation to TRIER data. This enabled us to get distance correlation plots from two triple-labeled protein samples that were in good agreement with DEER data and simulations. With such information it should then be possible to assign peaks in DEER distance distributions for macromolecules that can exist in more than one conformation.
  • Probing How Counterion Structure and Dynamics Determine Polyelectrolyte Solutions Using EPR Spectroscopy
    Item type: Review Article
    Hinderberger, Dariush; Spiess, Hans W.; Jeschke, Gunnar (2010)
    Applied Magnetic Resonance
    In this review article, we describe how methods of electron paramagnetic resonance (EPR) spectroscopy were used to investigate polyion–counterion interactions in polyelectrolyte solutions. This subject is usually treated experimentally by light, X-ray, or neutron scattering techniques. It is shown that a large arsenal of EPR spectroscopic methods–from various sophisticated methods of line shape analysis of continuous-wave EPR, via electron spin echo envelope modulation, nanoscale distance measurements through double electron–electron resonance to high-field pulse EPR–can be used to characterize the intrinsically complicated structures formed in polyelectrolyte solutions. We show that even polymer physical models such as scaling relations can be tested in this way. The distinguishing feature with respect to the numerous scattering studies in this area is that EPR techniques are local methods, and by employing spin-carrying (i.e., EPR-active) probe ions, it is possible to examine polyelectrolytes from the counterions’ point of view.
  • DeerAnalysis2006 - A Comprehensive Software Package for Analyzing Pulsed ELDOR Data
    Item type: Journal Article
    Jeschke, Gunnar; Chechik, Victor; Ionita, Petre; et al. (2006)
    Applied Magnetic Resonance
  • Measurement of spin-lattice relaxation times with longitudinal detection
    Item type: Journal Article
    Granwehr, J.; Schweiger, A. (2001)
    Applied Magnetic Resonance
  • Data Analysis Procedures for Pulse ELDOR Measurements of Broad Distance Distributions
    Item type: Journal Article
    Jeschke, Gunnar; Panek, Grazyna; Godt, Adelheid; et al. (2004)
    Applied Magnetic Resonance
  • NMR studies of two unusual f-electron metals
    Item type: Journal Article
    Gavilano, J. L.; Ambrosini, B.; Ott, H. R. (2000)
    Applied Magnetic Resonance
  • Rotamer Modelling of Cu(II) Spin Labels Based on the Double-Histidine Motif
    Item type: Journal Article
    Ghosh, Shreya; Saxena, Sunil; Jeschke, Gunnar (2018)
    Applied Magnetic Resonance
    Spin labels attached to two residues of a protein chain have less conformational flexibility than those attached to a single residue and thus lead to a narrower spatial distribution of the unpaired electron. The case of Cu²⁺ labels based on the double-histidine (dHis) motif is of particular interest, as it combines the advantage of precise localization of the unpaired electron with a labelling scheme orthogonal to the more common cysteine-based labelling. Here, we introduce an approach for in silico spin labelling of a protein by dHis motifs and Cu²⁺ complexes of iminodiacetic acid or nitrilotriacetic acid. We discuss a computerized scan for native histidine pairs that might be prone to bind such Cu²⁺ complexes and spin-labelling site pair scans that can identify suitable double mutants for labelling. Predicted distance distributions between two Cu²⁺ labels are compared to experimental distance distributions. We also test the hypothesis that elastic network modelling of conformational transitions with Cu²⁺-dHis labels can provide more accurate structural models than with nitroxide labels.
  • Heterogeneity in the Nitroxide Micro-Environment
    Item type: Journal Article
    Bordignon, Enrica; Brutlach, H.; Urban, L.; et al. (2010)
    Applied Magnetic Resonance
    This study aims to investigate the g xx heterogeneity of the g-tensor commonly observed in high-field electron paramagnetic resonance (EPR) spectra of nitroxide spin-labeled sites in proteins. This heterogeneity is addressed in terms of spin-label populations characterized by different polarity and H-bonding properties of the nitroxide micro-environment. The g xx value for each population is determined from the fit of continuous-wave high-field spectra obtained at 95, 275 and 360 GHz with a series of nitroxide spin-labels covalently attached to different sites in both membrane and water-soluble proteins. The spin-labeled proteins investigated include sensory rhodopsin II and its cognate transducer molecule (HtrII) from Natronomonas pharaonis both in micelles and membranes, bacteriorhodopsin from Halobacterium salinarum in native purple membrane lipid bilayers and water-soluble colicin A from Escherichia coli. To avoid contributions to the g xx spectral features of the nitroxide label due to nuclear quadrupole interactions arising from 14N nuclei, and to simplify the nitrogen hyperfine pattern, methanethiosulfonate spin labels, containing the 15N isotope (I = 1/2) in some experiments, were employed. A consistent analysis of all multi-frequency EPR spectra revealed three distinct g xx values, g i xx , for each investigated position of the labeled proteins. In contrast, distinctly different nitrogen hyperfine splittings A zz of the nitroxides in the various labeled proteins could not be resolved, but rather an average hyperfine splitting 𝐴�¯𝑧�𝑧� was obtained. The g i xx values as well as the fractions of the different nitroxide populations were found to be correlated with the average hyperfine constant 𝐴�¯𝑧�𝑧�, a parameter which likewise is known to be sensitive to the local polarity of the spin-label micro-environment. Plotting the different g i xx values obtained for each EPR spectrum versus 𝐴�¯𝑧�𝑧� of the labeled proteins reveals new interesting aspects of the nitroxide label micro-environment in terms of polarity and H-bonding propensity (proticity). Linear approximations of the different regions of the plot g i xx versus 𝐴�¯𝑧�𝑧� are presented and compared with theoretical and experimental data available from the literature.
  • High-field EPR studies on polymer film formation from colloidal dispersions
    Item type: Journal Article
    Cramer, Sibylle; Bauer, Christoph; Jeschke, Gunnar; et al. (2001)
    Applied Magnetic Resonance
  • Probeheads and Instrumentation for Pulse EPR and ENDOR Spectroscopy with Chirped Radio Frequency Pulses and Magnetic Field Steps
    Item type: Journal Article
    Forrer, Jörg; Pfenninger, Susanne; Sierra, Gustavo; et al. (1996)
    Applied Magnetic Resonance
Publications 1 - 10 of 19