Publication year: 2011 Source: Journal of Magnetic Resonance, Available online 9 September 2011
Dmitry*Shishmarev, Gottfried*Otting
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 sample tube within about 5 ms following a 165pulse. This can be exploited in water flip-back versions of NOESY and TOCSY experiments of proteins, but care must be taken to limit the effect of the radiation-damping field from the water on the Hprotons. Long water-selective pulses can be applied only following corrections. We developed a program for correcting pulse shapes if ? is non-zero. The WATERGATE scheme is shown to be insensitive to imperfections introduced by radiation damping. Graphical abstract
Highlights
? Radiation damping (RD) on cryoprobes is stronger than meets the eye. ? RD parameters differ between direct and indirect detection modes. ? RD-driven water flip-back in NOESY and TOCSY for minimal Hattenuation in proteins. ? Software to correct pulse shapes for ? and ? parameters of radiation damping.
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
[Question from NMRWiki Q&A forum] How to study polymer degradation by gamma and X-Ray radiation?
How to study polymer degradation by gamma and X-Ray radiation?
Hi, I was asked to study polyethylene degradated by gamma and Xrays. I planed to measure relaxations rates, but which one is the most relevant to highlight chain degradation? T1, T2, but on 1H or 13C? By reading some articles, I feel T2 is not very interesting, right? T1rho experiments seems to give good results, I have found 2 sequences in Bruker's library, T1rhoX (CP step then variable length spin lock pulse on 13C channel) and T1rhoH (CP step then variable length spin lock pulse on 1H channel), and there is also the more...
In Vivo NMR Metabolic Profiling of Fabrea salina Reveals Sequential Defense Mechanisms against Ultraviolet Radiation.
In Vivo NMR Metabolic Profiling of Fabrea salina Reveals Sequential Defense Mechanisms against Ultraviolet Radiation.
In Vivo NMR Metabolic Profiling of Fabrea salina Reveals Sequential Defense Mechanisms against Ultraviolet Radiation.
Biophys J. 2011 Jan 5;100(1):215-24
Authors: Marangoni R, Paris D, Melck D, Fulgentini L, Colombetti G, Motta A
Fabrea salina is a hypersaline ciliate that is known to be among the strongest ultraviolet (UV)-resistant microorganisms; however, the molecular mechanisms of this resistance are almost unknown. By means...
Radiation Damping on Cryoprobes
Linear Mode
