Real-time imaging of the spatial distribution of rf-heating in NMR samples during broadband decoupling

Wimmer, Reinhard; Wider, Gerhard

doi:10.1016/j.jmr.2007.04.014

Cited by 6 publications

(9 citation statements)

References 17 publications

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“…Experimentally, the high-power spin-lock fields used in RF RD may stress the NMR probe and/or produce undesirable heating of the sample [45, 157]. Though not as commonly used as CPMG RD, RF RD is the method of choice for exchange processes in the μs time window.…”

Section: Nmr Methodsmentioning

confidence: 99%

An introduction to NMR-based approaches for measuring protein dynamics

Kleckner¹,

Foster²

2011

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

471

498

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Proteins are inherently flexible at ambient temperature. At equilibrium, they are characterized by a set of conformations that undergo continuous exchange within a hierarchy of spatial and temporal scales ranging from nanometers to micrometers and femtoseconds to hours. Dynamic properties of proteins are essential for describing the structural bases of their biological functions including catalysis, binding, regulation and cellular structure. Nuclear magnetic resonance (NMR) spectroscopy represents a powerful technique for measuring these essential features of proteins. Here we provide an introduction to NMR-based approaches for studying protein dynamics, highlighting eight distinct methods with recent examples, contextualized within a common experimental and analytical framework. The selected methods are (1) Real-time NMR, (2) Exchange spectroscopy, (3) Lineshape analysis, (4) CPMG relaxation dispersion, (5) Rotating frame relaxation dispersion, (6) Nuclear spin relaxation, (7) Residual dipolar coupling, (8) Paramagnetic relaxation enhancement.

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Section: Nmr Methodsmentioning

confidence: 99%

An introduction to NMR-based approaches for measuring protein dynamics

Kleckner¹,

Foster²

2011

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics

471

498

View full text Add to dashboard Cite

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“…With this method, we estimated the B 1 profile of the solenoidal coil and the LLC in the circuit by applying Eq. (9). For comparison, these data were added to the numerical data in Fig.…”

Section: Resonatormentioning

confidence: 99%

“…For solid-state magic-angle-spinning NMR, where solenoidal coils are widely used, the appearance of high NMR frequencies may lead to a degradation of rf homogeneity and an increase of fringe electric fields in the sample volume that may interact with the bulk electric properties of the sample [1][2][3][4][5][6][7][8][9][10][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…In addition dielectric polarization losses may arise from the polarization of the water molecules or the biomacromolecules themselves by the presence of an electric field. An rf electric field E 1 present in such samples will interact with the sample, characterized by a complex-valued effective bulk permittivity e r , where this interaction leads to the dissipation of energy by rf heating [1][2][3]9]. Although applications exist where sample heating during the experiment is intended and appreciated [4,5] it is to be avoided for most biological samples, where it can be catastrophic.…”

Section: Introductionmentioning

confidence: 99%

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Resonator with reduced sample heating and increased homogeneity for solid-state NMR

Krahn

Priller

Emsley

et al. 2008

Journal of Magnetic Resonance

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“…This is being used in many practical applications, in particular to calibrate the temperature unit of the NMR probe upon installation (van Geet 1970; Bornais and Brownstein 1978; Levy et al 1980; Ammann et al 1982), to map the local temperature in steady and non-steady state conditions (Wimmer and Wider 2007), to detect thermal convection currents (Jerschow 2000), or to improve the temperature stabilization (Keiichiro 1991). However, since chemical shifts are not only dependent on the temperature, but also on other sample parameters, like the pH value, the salt concentration, etc., the measured chemical shifts can be interpreted as temperatures only for samples with an exactly defined composition, e.g.…”

Section: Introductionmentioning

confidence: 99%

The T-lock: automated compensation of radio-frequency induced sample heating

2009

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Modern high-field NMR spectrometers can stabilize the nominal sample temperature at a precision of less than 0.1 K. However, the actual sample temperature may differ from the nominal value by several degrees because the sample heating caused by high-power radio frequency pulses is not readily detected by the temperature sensors. Without correction, transfer of chemical shifts between different experiments causes problems in the data analysis. In principle, the temperature differences can be corrected by manual procedures but this is cumbersome and not fully reliable. Here, we introduce the concept of a "T-lock", which automatically maintains the sample at the same reference temperature over the course of different NMR experiments. The T-lock works by continuously measuring the resonance frequency of a suitable spin and simultaneously adjusting the temperature control, thus locking the sample temperature at the reference value. For three different nuclei, 13 C, 17 O and 31 P in the compounds alanine, water, and phosphate, respectively, the T-lock accuracy was found to be < 0.1 K. The use of dummy scan periods with variable lengths allows a reliable establishment of the thermal equilibrium before the acquisition of an experiment starts.

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Real-time imaging of the spatial distribution of rf-heating in NMR samples during broadband decoupling

Cited by 6 publications

References 17 publications

An introduction to NMR-based approaches for measuring protein dynamics

An introduction to NMR-based approaches for measuring protein dynamics

Resonator with reduced sample heating and increased homogeneity for solid-state NMR

The T-lock: automated compensation of radio-frequency induced sample heating

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