Biological Applications of Time Domain ESR

Thomann, H.; Dalton, Larry R.; Dalton, Lauraine A.

doi:10.1007/978-1-4615-6546-8_4

Cited by 13 publications

(8 citation statements)

References 66 publications

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“…As is well known, magnetic resonance spectroscopy can not only probe the static structural details of a molecule but also details of its dynamic properties [80][81][82]. If the motion is on the time scale of the EPR experiment, spin relaxation and, thereby, line broadening can be observed in the cw EPR spectrum.…”

Section: Conformational Cofactor Dynamicsmentioning

confidence: 97%

The Magic of Disaccharide Glass Matrices for Protein Function as Decoded by High-Field EPR and FTIR Spectroscopy

et al. 2015

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The structural and dynamical interaction of proteins with their microenvironment in disordered matrices plays a decisive role for their function; EPR spectroscopy is a powerful tool for shading light onto the molecular mechanisms of this protein-matrix interplay. To clarify the molecular mechanisms of disaccharide bioprotection, we studied the structure and dynamics of spin-labeled systems and photosynthetic reaction centers (RCs) in sucrose and trehalose matrices at different hydration levels by means of cw and pulse high-field 95 GHz (W-band) EPR as well as by FTIR. In this minireview, we summarize and discuss EPR and FTIR experiments showing that the anhydrobiotic state of the RC-trehalose system (1) is not the result of matrix-induced changes of the local structure of the charge-separated radical-pair cofactors, P Áþ 865 and Q ÁÀ A , and (2) is not the result of changes of local dynamics and local hydrogen bonding of Q A in its binding pocket. Rather, the extreme impairment of RC dynamics caused by incorporation into the dehydrated trehalose matrix, which also protects it against thermal denaturation, originates in the high rigidity, already at room temperature, of the dry trehalose glass matrix coating the RC protein surface. This surface hydrogen-bonding scaffold shifts the correlation time of thermal conformational fluctuations into the non-biological time domain. Another intriguing aspect of disaccharide bioprotection is the superior The authors dedicate this work to Giovanni Giacometti on the occasion of his 85th birthday. AppliedMagnetic Resonance efficiency of trehalose versus sucrose matrices in stabilizing the anhydrobiotic state of proteins. To clarify the molecular basis of this specificity, glassy trehalose-water and sucrose-water binary systems, incorporating a nitroxide radical as spin probe, have been studied by high-field W-band EPR spectroscopy at different water contents. Analysis of the EPR spectra revealed a different structural and dynamical organization in the sucrose and trehalose matrix, only the trehalose being homogeneous in terms of residual water and nitroxide distribution.

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Section: Conformational Cofactor Dynamicsmentioning

confidence: 97%

The Magic of Disaccharide Glass Matrices for Protein Function as Decoded by High-Field EPR and FTIR Spectroscopy

et al. 2015

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“…Although the sample contained only about l O I 3 triplet spins, it was possible by spectrum accumulation to completely determine the hyperfine tensors for the two magnetically equivalent protons from the angular dependence of the nuclear frequencies w ,~ [Eq. (13)]. The ENDOR data show that the molecular symmetry departs considerably from D2,,.…”

Section: Pulsed Endor Spectroscopy Of Free Porphyrin Busesmentioning

confidence: 97%

Pulsed Electron Spin Resonance Spectroscopy: Basic Principles, Techniques, and Examples of Applications [New Analytical Methods (43)]

Schweiger

1991

Angew. Chem. Int. Ed. Engl.

193

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Electron spin resonance (ESR) spectroscopy has recently undergone a major innovative advance, which is described by the magical phrase pulsed ESR. To the spectroscopist who rubs this Aladdin's lamp there now opens up the mysterious world of spin acrobatics with its many novel and surprising phenomena. The use of pulse techniques makes it possible to reduce measurement times, increase sensitivity, improve resolution and simplify spectra. This article describes the most important pulse techniques used in ESR spectroscopy. Mathematical descriptions are kept to a minimum, space being devoted instead to examples of applications in various areas of chemical research.

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“…127 The coordination structure and oxidation state of the V0 2 + ion in vivo in bone samples has been determined with ESEEM spectroscopy. 12 s…”

Section: Paramagnetic Metalsmentioning

confidence: 98%

“…By using the time-dependent Schrodinger equation, the Liouville-von Neumann equation is obtained 2 ' 1 r, (12) where H(t) is the spin Hamiltonian, which has formal solution: (13) By selecting a suitable rotating frame system, the Hamiltonian can often be made time-independent within each evolution period. Then the evolution of the density matrix can be obtained in successive steps in which a static Hamiltonian acts on the system.…”

Section: Quantum Mechanical Treatment Of Pulse Experimentsmentioning

confidence: 99%