The effectiveness of 1H decoupling in the 13C MAS NMR of paramagnetic solids: An experimental case study incorporating copper(II) amino acid complexes

Willans, Mathew J.; Sears, Devin N.; Wasylishen, Roderick E.

doi:10.1016/j.jmr.2007.11.012

Cited by 12 publications

(15 citation statements)

References 83 publications

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“…3 shows the corresponding 13 C MAS spectra of dehydrated and some selected water-loaded Cu 3 (BTC) 2 samples measured without 1 H decoupling. The presence of strong paramagnetic shifts for both aromatic and carboxylate carbon resonances, which is common for compounds containing paramagnetic metal ions, 24,27,28 can clearly be seen. For the dehydrated sample the signals arise at 228 and À86 ppm for the aromatic and the carboxylate carbon, respectively.…”

Section: H Nmr Spinning Sideband Analysismentioning

confidence: 91%

“…13 C MAS spectra were measured using direct excitation without high power 1 H-decoupling (DPMAS). For comparison, for dehydrated Cu 3 (BTC) 2 , experiments were also carried out with high power 1 H-decoupling using the XiX decoupling sequence, 36 which was optimal for paramagnetic systems 28 but showed no difference in resolution and linewidth (ESIw, S-2). Therefore, all experiments were carried out without high power 1 H-decoupling.…”

Section: Nmr Measurementsmentioning

confidence: 99%

“…The paramagnetic influence is known to strongly affect the magnetic properties of surrounding nuclei. [25][26][27][28][29][30] Signal assignments are difficult because of large paramagnetic shifts and line broadening effects. The paramagnetic shift arises due to the hyperfine interactions of the unpaired electron of copper with the neighboring nuclei.…”

Section: Introductionmentioning

confidence: 99%

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Effects of varying water adsorption on a Cu3(BTC)2 metal–organic framework (MOF) as studied by 1H and 13C solid-state NMR spectroscopy

Gul‐E‐Noor

Jee

Pöppl

et al. 2011

Phys. Chem. Chem. Phys.

147

129

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The process of water adsorption on a dehydrated Cu(3)(BTC)(2) (copper (II) benzene 1,3,5-tricarboxylate) metal-organic framework (MOF) was studied with (1)H and (13)C solid-state NMR. Different relative amounts of water (0.5, 0.75, 1, 1.5, 2, and 5 mole equivalents with respect to copper) were adsorbed via the gas phase. (1)H and (13)C MAS NMR spectra of dehydrated and water-loaded Cu(3)(BTC)(2) samples gave evidence on the structural changes due to water adsorption within the MOF material as well as information on water dynamics. The analysis of (1)H spinning sideband intensities reveals differences in the (1)H-(63/65)Cu hyperfine coupling between dehydrated and water-loaded samples. The investigation was continued for 60 days to follow the stability of the Cu(3)(BTC)(2) network under humid conditions. NMR data reveal that Cu(3)(BTC)(2) decomposes quite fast with the decomposition being different for different water contents.

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Section: H Nmr Spinning Sideband Analysismentioning

confidence: 91%

Section: Nmr Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of varying water adsorption on a Cu3(BTC)2 metal–organic framework (MOF) as studied by 1H and 13C solid-state NMR spectroscopy

Gul‐E‐Noor

Jee

Pöppl

et al. 2011

Phys. Chem. Chem. Phys.

147

129

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“…Furthermore, the homogeneous part of the linewidth is effectively reduced by performing DNP experiments with fast MAS (40 kHz) and 150 kHz decoupling power, with bulk coherence lifetimes of 24 ms, corresponding to refocused linewidths as narrow as 13 Hz for the 13 C′ spins (Figure a). Both fast MAS and high‐power decoupling provide better averaging of anisotropic interactions and of paramagnetic effects caused by the radical, yielding at 800 MHz an observed 13 C linewidth mainly governed by inhomogeneous broadening. Notably, the resolution under identical conditions, but in absence of the radical is unchanged (Supporting Information, Figure S5), while the coherence lifetimes are noticeably longer (Figure a).…”

Section: Figurementioning

confidence: 99%

Dynamic Nuclear Polarization‐Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic‐Angle Spinning

et al. 2018

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Dynamic nuclear polarization (DNP) is apowerful way to overcome the sensitivity limitation of magic-anglespinning (MAS) NMR experiments.However,the resolution of the DNP NMR spectra of proteins is compromised by severe line broadening associated with the necessity to perform experiments at cryogenic temperatures and in the presence of paramagnetic radicals.H igh-quality DNP-enhanced NMR spectra of the Acinetobacter phage 205 (AP205) nucleocapsid can be obtained by combining high magnetic field (800 MHz) and fast MAS (40 kHz). These conditions yield enhanced resolution and long coherence lifetimes allowing the acquisition of resolved 2D correlation spectra and of previously unfeasible scalar-based experiments.T his enables the assignment of aromatic resonances of the AP205 coat protein and its packaged RNA, as well as the detection of long-range contacts, which are not observed at room temperature,o pening new possibilities for structure determination.Dynamic nuclear polarization (DNP) allows transfer of polarization from the unpaired electrons of ap aramagnetic center to the surrounding nuclei, enhancing the magic-anglespinning (MAS) NMR signals by several orders of magnitude. [1] Thetechnique has been successfully applied in various fields from chemistry and materials to structural and cell biology.H owever,d espite convincing demonstrations on fibrils, [2] membrane-embedded proteins, [3] virus capsids, [4] and whole-cell assemblies, [5] thes ensitivity enhancement provided by DNP on biological systems is always associated with an umber of issues.W hile high-resolution solid-state MAS NMR spectra of proteins can be nowadays obtained at temperatures above 273 K, the resolution of the DNP NMR spectra of proteins is compromised by severe line broadening associated with the necessity to perform experiments at cryogenic temperatures (at about 100 K) and in the presence of paramagnetic radicals.F urthermore,D NP spectra of protein samples are currently almost exclusively acquired at moderate magnetic fields (usually 9.4 T) for maximum DNP enhancements and using 3.2 mm rotors with MAS rates up to 15 kHz. Under these experimental conditions,t he lines are broadened by both homogeneous broadening,o wing to incomplete averaging of nuclear and hyperfine interactions, and inhomogeneous broadening,a rising from protein conformational disorder. [6] Thelack of resolution associated with the DNP enhancements is therefore amajor obstacle for the detailed structural study of uniformly labeled biomolecular samples.This limitation has been previously addressed by using increased temperatures (180-200 K) [7] and higher magnetic field strengths [8] at the expense of lower DNP enhancements, as well as by exploring improved sample preparation methods. [9] Whilst these initial attempts have shown the potential for improving resolution in DNP spectra, af urther improvement is imperative to take full advantage of the signal amplification potentially provided by DNP.O ne factor that holds promise is the MAS rate.T he availability of prob...

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“…the 13 C' spins ( Figure 2a). Both fast MAS and high-power decoupling provide better averaging of anisotropic interactions and of paramagnetic effects caused by the radical, [17] yielding at 800 MHz an observed 13 Cl inewidth mainly governed by inhomogeneous broadening.N otably,t he resolution under identical conditions,but in absence of the radical is unchanged (Supporting Information, Figure S5), while the coherence lifetimes are noticeably longer (Figure 2a). This indicates as ignificant paramagnetic relaxation enhancement from the radical, which is hidden inside the apparent linewidth.…”

mentioning

confidence: 99%

Dynamic Nuclear Polarization‐Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic‐Angle Spinning

et al. 2018

View full text Add to dashboard Cite

Dynamic nuclear polarization (DNP) is a powerful way to overcome the sensitivity limitation of magic-angle-spinning (MAS) NMR experiments. However, the resolution of the DNP NMR spectra of proteins is compromised by severe line broadening associated with the necessity to perform experiments at cryogenic temperatures and in the presence of paramagnetic radicals. High-quality DNP-enhanced NMR spectra of the Acinetobacter phage 205 (AP205) nucleocapsid can be obtained by combining high magnetic field (800 MHz) and fast MAS (40 kHz). These conditions yield enhanced resolution and long coherence lifetimes allowing the acquisition of resolved 2D correlation spectra and of previously unfeasible scalar-based experiments. This enables the assignment of aromatic resonances of the AP205 coat protein and its packaged RNA, as well as the detection of long-range contacts, which are not observed at room temperature, opening new possibilities for structure determination.

show abstract

The effectiveness of 1H decoupling in the 13C MAS NMR of paramagnetic solids: An experimental case study incorporating copper(II) amino acid complexes

Cited by 12 publications

References 83 publications

Effects of varying water adsorption on a Cu3(BTC)2 metal–organic framework (MOF) as studied by 1H and 13C solid-state NMR spectroscopy

Effects of varying water adsorption on a Cu3(BTC)2 metal–organic framework (MOF) as studied by 1H and 13C solid-state NMR spectroscopy

Dynamic Nuclear Polarization‐Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic‐Angle Spinning

Dynamic Nuclear Polarization‐Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic‐Angle Spinning

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