The University of Ottawa has recently been funded for a 600 MHz NMR spectrometer with a cryogenetically cooled probe. Cryoprobes differ from conventional NMR probes in that the rf circuits and preamplifiers are cooled with cold helium gas while the sample is maintained at ambient temperature. The benefit of cryogenically cooled electronics compared to room temperature electronics is that the thermal noise in the system is reduced at cryogenic temperatures while the NMR signal remains constant for the sample at ambient temperature. The signal-to-noise ratio in an NMR spectrum acquired in a cryoprobe is therefore increased dramatically compared to a conventional probe, typically by a factor of 4. This allows for data collection times on the order of 16 times shorter than those using conventional probes as well as lower detection limits. This principle can be crudely demonstrated by replacing the NMR probe with a 50 ? load and collecting "NMR" data on the load at both high and low temperatures. The "NMR spectra" in the figure below were collected (without using an rf pulse) on a 50 ? load outside of the magnet at room temperature (left panel) and in a dewar of liquid nitrogen at 77 K (right panel). The noise collected in the 77 K spectrum is 35% lower than that in the room temperature spectrum demonstrating the lower thermal noise at lower temperatures.
This effect is dramatically increased in a crypoprobe which cools the electronics of both the rf probe circuits and preamplifiers to temperatures much lower than 77 K.
Thermal stability of chicken brain α-spectrin repeat 17: a spectroscopic study
Thermal stability of chicken brain α-spectrin repeat 17: a spectroscopic study
Abstract Spectrin is a rod-like multi-modular protein that is mainly composed of triple-helical repeats. These repeats show very similar 3D-structures but variable conformational and thermodynamical stabilities, which may be of great importance for the flexibility and dynamic behaviour of spectrin in the cell. For instance, repeat 17 (R17) of the chicken brain spectrin α-chain is four times less stable than neighbouring repeat 16 (R16) in terms of ∆G. The structure of spectrin repeats has mainly been...
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DNP by Thermal Mixing under Optimized Conditions Yields >60 000-fold Enhancement of 89Y NMR Signal
DNP by Thermal Mixing under Optimized Conditions Yields >60 000-fold Enhancement of 89Y NMR Signal
Lloyd Lumata, Ashish K. Jindal, Matthew E. Merritt, Craig R. Malloy, A. Dean Sherry and Zoltan Kovacs
http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/0/jacsat.ahead-of-print/ja201880y/aop/images/medium/ja-2011-01880y_0010.gif
Journal of the American Chemical Society
DOI: 10.1021/ja201880y
http://feeds.feedburner.com/~ff/acs/jacsat?d=yIl2AUoC8zA
http://feeds.feedburner.com/~r/acs/jacsat/~4/lZjUD7bs_fI
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[NMR paper] Contribution of the multi-turn segment in the reversible thermal stability of hyperth
Contribution of the multi-turn segment in the reversible thermal stability of hyperthermophile rubredoxin: NMR thermal chemical exchange analysis of sequence hybrids.
Related Articles Contribution of the multi-turn segment in the reversible thermal stability of hyperthermophile rubredoxin: NMR thermal chemical exchange analysis of sequence hybrids.
Biophys Chem. 2005 Jun 1;116(1):57-65
Authors: LeMaster DM, Tang J, Paredes DI, Hernández G
Pyrococcus furiosus (Pf) rubredoxin is the most thermostable protein characterized to date. Reflecting the...
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[NMR paper] Thermal stability of calmodulin and mutants studied by (1)H-(15)N HSQC NMR measuremen
Thermal stability of calmodulin and mutants studied by (1)H-(15)N HSQC NMR measurements of selectively labeled Ile proteins.
Related Articles Thermal stability of calmodulin and mutants studied by (1)H-(15)N HSQC NMR measurements of selectively labeled Ile proteins.
Biochemistry. 2002 May 28;41(21):6850-9
Authors: Biekofsky RR, Martin SR, McCormick JE, Masino L, Fefeu S, Bayley PM, Feeney J
Calmodulin, the Ca(2+)-dependent activator of many cellular processes, contains two well-defined structural domains, each of which binds two Ca(2+) ions....
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[NMR paper] Mechanisms for the enhanced thermal stability of a mutant of transcription factor 1 a
Mechanisms for the enhanced thermal stability of a mutant of transcription factor 1 as explained by (1)H, (15)N and (13)C NMR chemical shifts and secondary structure analysis.
Related Articles Mechanisms for the enhanced thermal stability of a mutant of transcription factor 1 as explained by (1)H, (15)N and (13)C NMR chemical shifts and secondary structure analysis.
Biochim Biophys Acta. 2000 Mar 16;1478(1):113-24
Authors: Vu HM, Liu W, Grove A, Geiduschek EP, Kearns DR
A variant of the bacteriophage SPO1-encoded transcription factor 1 (TF1)...
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11-18-2010 09:15 PM
[NMR paper] Effect of thermal denaturation on water-collagen interactions: NMR relaxation and dif
Effect of thermal denaturation on water-collagen interactions: NMR relaxation and differential scanning calorimetry analysis.
Related Articles Effect of thermal denaturation on water-collagen interactions: NMR relaxation and differential scanning calorimetry analysis.
Biopolymers. 1999 Dec;50(7):690-6
Authors: Rochdi A, Foucat L, Renou JP
The dependence of the proton spin-lattice relaxation rate, and of the enthalpy and temperature of denaturation on water content, were studied by nmr and differential scanning calorimetry (DSC) in native and...
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[NMR paper] NMR analysis of staphylococcal nuclease thermal quench refolding kinetics.
NMR analysis of staphylococcal nuclease thermal quench refolding kinetics.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc.gif Related Articles NMR analysis of staphylococcal nuclease thermal quench refolding kinetics.
Protein Sci. 1993 May;2(5):851-8
Authors: Kautz RA, Fox RO
Thermally unfolded staphylococcal nuclease has been rapidly...
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[Stan NMR blog] Noise Figure and Equivalent Input Noise
Noise Figure and Equivalent Input Noise
An educational article about the definitions of - and the relation between - the two concepts.
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