Kuzhelev, A.A., et al., Room-temperature electron spin relaxation of nitroxides immobilized in trehalose: Effect of substituents adjacent to NO-group. J. Magn. Reson., 2016. 266: p. 1-7.
Trehalose has been recently promoted as efficient immobilizer of biomolecules for room-temperature EPR studies, including distance measurements between attached nitroxide spin labels. Generally, the structure of nitroxide influences the electron spin relaxation times, being crucial parameters for room-temperature pulse EPR measurements. Therefore, in this work we investigated a series of nitroxides with different substituents adjacent to NO-moiety including spirocyclohexane, spirocyclopentane, tetraethyl and tetramethyl groups. Electron spin relaxation times (T1, Tm) of these radicals immobilized in trehalose were measured at room temperature at X- and Q-bands (9/34 GHz). In addition, a comparison was made with the corresponding relaxation times in nitroxide-labeled DNA immobilized in trehalose. In all cases phase memory times Tm were close to 700 ns and did not essentially depend on structure of substituents. Comparison of temperature dependences of Tm at T = 80–300 K shows that the benefit of spirocyclohexane substituents well-known at medium temperatures (~100–180 K) becomes negligible at 300 K. Therefore, unless there are specific interactions between spin labels and biomolecules, the room-temperature value of Tm in trehalose is weakly dependent on the structure of substituents adjacent to NO-moiety of nitroxide. The issues of specific interactions and stability of nitroxide labels in biological media might be more important for room temperature pulsed dipolar EPR than differences in intrinsic spin relaxation of radicals.
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
From The DNP-NMR Blog:
Electron Spin–Lattice Relaxation Mechanisms of Nitroxyl Radicals in Ionic Liquids and Conventional Organic Liquids: Temperature Dependence of a Thermally Activated Process
A detailed understanding of the electron-spin relaxation mechanisms in polarizing agents used for DMP-NMR spectroscopy is crucial for the understanding of the DNP process and to optimize polarizing agents for different DNP applications. The entire study was performed at X-Band frequencies (9 GHz, 14 MHz 1H) and provides many details about the relaxation behavior of nitroxide radicals -...
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07-08-2015 11:11 PM
Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control
From The DNP-NMR Blog:
Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control
Sakaguchi, S., et al., Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2013. 317(0): p. 679-684.
http://www.sciencedirect.com/science/article/pii/S0168583X13008872
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01-23-2014 01:37 AM
Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control
From The DNP-NMR Blog:
Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control
Sakaguchi, S., et al., Proton polarization in photo-excited aromatic molecule at room temperature enhanced by intense optical source and temperature control. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2013(0).
http://www.sciencedirect.com/science/article/pii/S0168583X13008872
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11-21-2013 01:14 AM
Temperature Dependence of Electron Spin Relaxation of 2,2-Diphenyl-1-Picrylhydrazyl in Polystyrene
From The DNP-NMR Blog:
Temperature Dependence of Electron Spin Relaxation of 2,2-Diphenyl-1-Picrylhydrazyl in Polystyrene
Meyer, V., S. Eaton, and G. Eaton, Temperature Dependence of Electron Spin Relaxation of 2,2-Diphenyl-1-Picrylhydrazyl in Polystyrene. Appl. Magn. Reson., 2013. 44(4): p. 509-517.
http://dx.doi.org/10.1007/s00723-012-0417-7
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04-15-2013 10:32 PM
Effect of glassy modes on electron spin–lattice relaxation in solid ethanol
From the The DNP-NMR Blog:
Effect of glassy modes on electron spin–lattice relaxation in solid ethanol
Merunka, D., et al., Effect of glassy modes on electron spin–lattice relaxation in solid ethanol. J. Magn. Reson., 2013. 228(0): p. 50-58.
http://www.ncbi.nlm.nih.gov/pubmed/23357426
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04-15-2013 08:52 AM
Effect of freezing conditions on distances and their distributions derived from Double Electron Electron Resonance (DEER): A study of doubly-spin-labeled T4 lysozyme
Effect of freezing conditions on distances and their distributions derived from Double Electron Electron Resonance (DEER): A study of doubly-spin-labeled T4 lysozyme
Publication year: 2012
Source:Journal of Magnetic Resonance, Volume 216</br>
Elka R. Georgieva, Aritro S. Roy, Vladimir M. Grigoryants, Petr P. Borbat, Keith A. Earle, Charles P. Scholes, Jack H. Freed</br>
Pulsed dipolar ESR spectroscopy, DEER and DQC, require frozen samples. An important issue in the biological application of this technique is how the freezing rate and concentration of cryoprotectant...
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03-13-2012 03:33 PM
Effect of Freezing Conditions on Distances and Their Distributions Derived from Double Electron Electron Resonance (DEER): A Study of Doubly-Spin-Labeled T4 Lysozyme
Effect of Freezing Conditions on Distances and Their Distributions Derived from Double Electron Electron Resonance (DEER): A Study of Doubly-Spin-Labeled T4 Lysozyme
Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 24 January 2012</br>
Elka R.*Georgieva, Aritro S.*Roy, Vladimir M.*Grigoryants, Petr P.*Borbat, Keith A.*Earle, ...</br>
Pulsed dipolar ESR spectroscopy, DEER and DQC, require frozen samples. An important issue in the biological application of this technique is how the freezing rate and concentration of cryoprotectant could possibly affect the...
Room-temperature electron spin relaxation of nitroxides immobilized in trehalose: Effect of substituents adjacent to NO-group
Linear Mode
