Applications of two-dimensional NMR methods in photochemically induced dynamic nuclear polarization spectroscopy

1985 ◽  
Vol 107 (3) ◽  
pp. 705-706 ◽  
Author(s):  
R. M. Scheek ◽  
S. Stob ◽  
R. Boelens ◽  
K. Dijkstra ◽  
R. Kaptein
Keyword(s):  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Two Dimensional ◽  
Polarization Spectroscopy ◽  
Nmr Methods

scholarly journals Overhauser Dynamic Nuclear Polarization Enhanced Two-Dimensional Proton NMR Spectroscopy at Low Magnetic Fields

2021 ◽  
Author(s):  
Timothy J. Keller ◽  
Thorsten Maly
Keyword(s):  
Nmr Spectroscopy ◽  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Two Dimensional ◽  
Proton Nmr Spectroscopy ◽  
Line Broadening ◽  
Field Frequency ◽  
Low Field ◽  
Induced Field ◽  
Additional Hardware

Abstract. The majority of low-field Overhauser Dynamic Nuclear Polarization (ODNP) experiments reported so far have been 1D NMR experiments to study hydration dynamics. In this work, we demonstrate the application of ODNP-enhanced 2D J-resolved (JRES) spectroscopy to improve spectral resolution beyond the limit imposed by the line broadening introduced by the paramagnetic polarizing agent. Using this approach, we are able to separate the overlapping multiplets of ethyl crotonate into a 2nd dimension and clearly identify each chemical cite individually. Crucial to these experiments is interleaved spectral referencing, a method introduced to compensate for temperature induced field drifts over the course of the NMR acquisition. This method does not require additional hardware such as a field-frequency lock, which is especially challenging when designing compact systems.

scholarly journals Characterization of structural and folding properties of streptokinase by n.m.r. spectroscopy

1993 ◽  
Vol 290 (2) ◽  
pp. 313-319 ◽  
Author(s):  
A J Teuten ◽  
R W Broadhurst ◽  
R A G Smith ◽  
C M Dobson
Keyword(s):  
Protein Structure ◽  
Nuclear Polarization ◽  
Guanidine Hydrochloride ◽  
Two Dimensional ◽  
Polarization Spectroscopy ◽  
Histidine Residues ◽  
Chemically Induced ◽  
Dynamical Nuclear Polarization ◽  
Partially Folded States

The structure and physical properties of the fibrinolytic protein streptokinase have been investigated by 1H-n.m.r. spectroscopy. Well-resolved one- and two-dimensional spectra have been obtained for this molecule of molecular mass 47 kDa. Titration of all nine histidine residues has shown that these display a range of pKa values, between 5.6 and 8.2, revealing a variety of environments for these residues in the protein structure. Although at least eight histidine residues can be reversibly modified by diethylpyrocarbonate, only one is sufficiently exposed to be reactive towards photo-excited dye in chemically induced dynamical nuclear polarization spectroscopy experiments. Unfolding studies have been performed by thermal and chemical means. Evidence is presented here for several distinct unfolding transitions suggesting that the protein consists of at least three domains which have independent stability, and that the protein can exist in a number of partially folded states. For one of these, that formed in 2 M guanidine hydrochloride, it has been shown that the N-terminal region of the molecule is extensively unfolded, while other regions of the protein remain in native-like folded states.

scholarly journals Overhauser dynamic nuclear polarization (ODNP)-enhanced two-dimensional proton NMR spectroscopy at low magnetic fields

2021 ◽  
Vol 2 (1) ◽  
pp. 117-128
Author(s):  
Timothy J. Keller ◽  
Thorsten Maly
Keyword(s):  
Molecular Dynamics ◽  
Dynamic Nuclear Polarization ◽  
Nuclear Polarization ◽  
Two Dimensional ◽  
Proton Nmr Spectroscopy ◽  
Line Broadening ◽  
Field Frequency ◽  
Low Field ◽  
Induced Field ◽  
Additional Hardware

Abstract. The majority of low-field Overhauser dynamic nuclear polarization (ODNP) experiments reported so far have been 1D NMR experiments to study molecular dynamics and in particular hydration dynamics. In this work, we demonstrate the application of ODNP-enhanced 2D J-resolved (JRES) spectroscopy to improve spectral resolution beyond the limit imposed by the line broadening introduced by the paramagnetic polarizing agent. Using this approach, we are able to separate the overlapping multiplets of ethyl crotonate into a second dimension and clearly identify each chemical site individually. Crucial to these experiments is interleaved spectral referencing, a method introduced to compensate for temperature-induced field drifts over the course of the NMR acquisition. This method does not require additional hardware such as a field-frequency lock, which is especially challenging when designing compact systems.

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