Related ArticlesEffects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression.
Concepts Magn Reson Part A Bridg Educ Res. 2015 Sep;44A(5):252-262
Authors: Ishima R
Abstract
Abundant solvent nuclear spins, such as water protons in aqueous solution, cause radiation damping in NMR experiments. It is important to know how the effect of radiation damping appears in high-resolution protein NMR because macromolecular studies always require very high magnetic field strengths with a highly sensitive NMR probe that can easily cause radiation damping. Here, we show the behavior of water magnetization after a pulsed-field gradient (PFG) using nutation experiments at 900 MHz with a cryogenic probe: when water magnetization is located in the upper hemisphere (having +Z component, parallel to the external magnetic field), dephasing of the magnetization by a PFG effectively suppresses residual water magnetization in the transverse plane. In contrast, when magnetization is located in the lower hemisphere (having -Z component), the small residual transverse component remaining after a PFG is still sufficient to induce radiation damping. Based on this observation, we designed (1)H-(15)N HSQC experiments in which water magnetization is maintained in the upper hemisphere, but not necessarily along Z, and compared them with the conventional experiments, in which water magnetization is inverted during the t1 period. The result demonstrates moderate gain of signal-to-noise ratio, 0-28%. Designing the experiments such that water magnetization is maintained in the upper hemisphere allows shorter pulses to be used compared to the complete water flip-back and, thereby, is useful as a building block of protein NMR pulse programs in solution.
PMID: 27524944 [PubMed - as supplied by publisher]
[U. of Ottawa NMR Facility Blog] Radiation Damping and Pulse Calibration
Radiation Damping and Pulse Calibration
Radiation damping causes broadening in the NMR resonances of very strong signals (such as the 1H signal of pure water) as a result of currents induced in the coil from the strong transverse magnetization. Radiation damping can also produce asymmetry and phase irregularities in the affected resonances. These problems make pulse calibration by the standard nutation curve problematic when very strong signals are used for the calibration. The left-hand panel (black) of the figure below shows the standard 1H nutation curves for 0.1% H2O in D2O (bottom)...
Radiation Damping in Modern NMR Experiments: Progress and Challenges
Radiation Damping in Modern NMR Experiments: Progress and Challenges
Publication year: 2012
Source:Progress in Nuclear Magnetic Resonance Spectroscopy</br>
V.V. Krishnan, Nagarajan Murali</br>
Highlights
? Overview of radiation damping effects in biomolecular NMR experiments. ? Theory and modifications of Bloch Equations. ? Current status, artifacts, control, applications as well as constructive uses of radiation damping.</br>
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06-15-2012 02:10 PM
Measurement of amide hydrogen exchange rates with the use of radiation damping
Measurement of amide hydrogen exchange rates with the use of radiation damping
Abstract A simple method for measuring amide hydrogen exchange rates is presented, which is based on the selective inversion of water magnetization with the use of radiation damping. Simulations show that accurate exchange rates can be measured despite the complications of radiation damping and cross relaxation to the exchange process between amide and water protons. This method cannot eliminate the contributions of the exchange-relayed NOE and direct NOE to the measured exchange rates, but minimize the...
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09-30-2011 08:01 PM
Radiation Damping on Cryoprobes
Radiation Damping on Cryoprobes
Publication year: 2011
Source: Journal of Magnetic Resonance, Available online 9 September 2011</br>
Dmitry*Shishmarev, Gottfried*Otting</br>
Radiation damping on 600 and 800 MHz cryoprobes was investigated. The phase angle ? between a vector 90phase shifted to the precessing magnetization and the rf field induced in the coil was found to depend markedly on whether an FID was being acquired or not. The magnitude of the radiation-damping field was sufficiently strong to restore 95% of the equilibrium water magnetization of a 90% H2O sample in a 5 mm...
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09-12-2011 09:00 PM
Simultaneous convection compensation and solvent suppression in biomolecular NMR diffusion experiments
Simultaneous convection compensation and solvent suppression in biomolecular NMR diffusion experiments
Abstract Thermal convection and high intensity solvent resonances can significantly hamper diffusion estimates in pulsed gradient spin-echo nuclear magnetic resonance diffusion experiments on biomolecule samples. To overcome these two problems, a new double functional NMR diffusion sequence, double echo PGSTE-WATERGATE, is presented. The new sequence provides excellent convection compensation and solvent suppression (with a suppression factor in excess of at least 105 in a single scan)...
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01-09-2011 12:46 PM
[NMR paper] An emerging concept of biomolecular dynamics and function: applications of NMR & MRI.
An emerging concept of biomolecular dynamics and function: applications of NMR & MRI.
Related Articles An emerging concept of biomolecular dynamics and function: applications of NMR & MRI.
Magn Reson Med Sci. 2002;1(1):27-31
Authors: Kuwata K
A new concept of protein dynamics has emerged quite recently, and a crucial link between protein dynamics and function has been largely established using recent NMR techniques in the solution state. Protein structure is governed by the thermodynamic principle and may not necessarily be unique in the...
Effects of radiation damping for biomolecular NMR experiments in solution: a hemisphere concept for water suppression.
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