High-Frequency Dynamic Nuclear Polarization

Mak‐Jurkauskas, Melody L.; Griffin, Robert G.

doi:10.1002/9780470034590.emrstm1183

Cited by 8 publications

(8 citation statements)

References 36 publications

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“…First, in some of the initial DNP MAS protein spectra of bR photocycle intermediates recorded at ~90 K and 380 MHz/250 GHz that were published, the resolution of the retinal-Schiff peaks was ~1 ppm in 13 C- 15 N spectra. These results are documented in several publications [66–69] and discussed elsewhere [81] so we refer the reader to those references. However, the salient feature of bR is that it is a protein in its native “purple membrane” environment.…”

Section: Applications To Biological Systemssupporting

confidence: 76%

Mechanisms of dynamic nuclear polarization in insulating solids

Can

Griffin

2015

Journal of Magnetic Resonance

120

119

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Dynamic nuclear polarization (DNP) is a technique used to enhance signal intensities in NMR experiments by transferring the high polarization of electrons to their surrounding nuclei. The past decade has witnessed a renaissance in the development of DNP, especially at high magnetic fields, and its application in several areas including biophysics, chemistry, structural biology and materials science. Recent technical and theoretical advances have expanded our understanding of established experiments: for example, the cross effect DNP in samples spinning at the magic angle. Furthermore, new experiments suggest that our understanding of the Overhauser effect and its applicability to insulating solids needs to be re-examined. In this article, we summarize important results of the past few years and provide quantum mechanical explanations underlying these results. We also discuss future directions of DNP and current limitations, including the problem of resolution in protein spectra recorded at 80–100 K.

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Section: Applications To Biological Systemssupporting

confidence: 76%

Mechanisms of dynamic nuclear polarization in insulating solids

Can

Griffin

2015

Journal of Magnetic Resonance

120

119

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“…Several papers (122,(128)(129)(130)(131)(132) and reviews (7,125,133) have provided in-depth descriptions of these mechanisms. In this section, we briefly review the two most important mechanisms applicable to proteins, the SE and CE.…”

Section: Mechanismsmentioning

confidence: 98%

Magic Angle Spinning NMR of Proteins: High-Frequency Dynamic Nuclear Polarization and ¹H Detection

Andreas²,

Griffin

2015

Annu. Rev. Biochem.

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133

100

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Magic angle spinning (MAS) NMR studies of amyloid and membrane proteins and large macromolecular complexes are an important new approach to structural biology. However, the applicability of these experiments, which are based on (13)C- and (15)N-detected spectra, would be enhanced if the sensitivity were improved. Here we discuss two advances that address this problem: high-frequency dynamic nuclear polarization (DNP) and (1)H-detected MAS techniques. DNP is a sensitivity enhancement technique that transfers the high polarization of exogenous unpaired electrons to nuclear spins via microwave irradiation of electron-nuclear transitions. DNP boosts NMR signal intensities by factors of 10(2) to 10(3), thereby overcoming NMR's inherent low sensitivity. Alternatively, it permits structural investigations at the nanomolar scale. In addition, (1)H detection is feasible primarily because of the development of MAS rotors that spin at frequencies of 40 to 60 kHz or higher and the preparation of extensively (2)H-labeled proteins.

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“…Four main different mechanisms (depending on the experimental conditions) can account for the DNP effect, namely, the Overhauser effect (OE), the solid effect (SE), the cross effect (CE), and the thermal mixing (TM). A detailed demonstration of these mechanisms is out of the scope of this Feature article; for more details the reader is invited to refer to excellent DNP reviews. − In solids, these DNP mechanisms usually strongly rely on nuclear spin diffusion; indeed, in a first step the transfer of polarization occurs from the electron spins to the nearby core nuclear spins, and in a second step, nuclear spin diffusion propagates this polarization further away toward the bulk nuclear spins.…”

Section: Principles Of Dnpmentioning

confidence: 99%