BioNMR
NMR aggregator & online community since 2003
BioNMR    
Learn or help to learn NMR - get free NMR books!
 

Go Back   BioNMR > NMR community > News from NMR blogs
Advanced Search



Jobs Groups Conferences Literature Pulse sequences Software forums Programs Sample preps Web resources BioNMR issues


Webservers
NMR processing:
MDD
NMR assignment:
Backbone:
Autoassign
MARS
UNIO Match
PINE
Side-chains:
UNIO ATNOS-Ascan
NOEs:
UNIO ATNOS-Candid
UNIO Candid
ASDP
Structure from NMR restraints:
Ab initio:
GeNMR
Cyana
XPLOR-NIH
ASDP
UNIO ATNOS-Candid
UNIO Candid
Fragment-based:
BMRB CS-Rosetta
Rosetta-NMR (Robetta)
Template-based:
GeNMR
I-TASSER
Refinement:
Amber
Structure from chemical shifts:
Fragment-based:
WeNMR CS-Rosetta
BMRB CS-Rosetta
Homology-based:
CS23D
Simshift
Torsion angles from chemical shifts:
Preditor
TALOS
Promega- Proline
Secondary structure from chemical shifts:
CSI (via RCI server)
TALOS
MICS caps, β-turns
d2D
PECAN
Flexibility from chemical shifts:
RCI
Interactions from chemical shifts:
HADDOCK
Chemical shifts re-referencing:
Shiftcor
UNIO Shiftinspector
LACS
CheckShift
RefDB
NMR model quality:
NOEs, other restraints:
PROSESS
PSVS
RPF scores
iCing
Chemical shifts:
PROSESS
CheShift2
Vasco
iCing
RDCs:
DC
Anisofit
Pseudocontact shifts:
Anisofit
Protein geomtery:
Resolution-by-Proxy
PROSESS
What-If
iCing
PSVS
MolProbity
SAVES2 or SAVES4
Vadar
Prosa
ProQ
MetaMQAPII
PSQS
Eval123D
STAN
Ramachandran Plot
Rampage
ERRAT
Verify_3D
Harmony
Quality Control Check
NMR spectrum prediction:
FANDAS
MestReS
V-NMR
Flexibility from structure:
Backbone S2
Methyl S2
B-factor
Molecular dynamics:
Gromacs
Amber
Antechamber
Chemical shifts prediction:
From structure:
Shiftx2
Sparta+
Camshift
CH3shift- Methyl
ArShift- Aromatic
ShiftS
Proshift
PPM
CheShift-2- Cα
From sequence:
Shifty
Camcoil
Poulsen_rc_CS
Disordered proteins:
MAXOCC
Format conversion & validation:
CCPN
From NMR-STAR 3.1
Validate NMR-STAR 3.1
NMR sample preparation:
Protein disorder:
DisMeta
Protein solubility:
camLILA
ccSOL
Camfold
camGroEL
Zyggregator
Isotope labeling:
UPLABEL
Solid-state NMR:
sedNMR


Reply
Thread Tools Search this Thread Rate Thread Display Modes
  #1  
Unread 08-07-2020, 08:10 PM
nmrlearner's Avatar
Senior Member
 
Join Date: Jan 2005
Posts: 23,135
Points: 193,617, Level: 100
Points: 193,617, Level: 100 Points: 193,617, Level: 100 Points: 193,617, Level: 100
Level up: 0%, 0 Points needed
Level up: 0% Level up: 0% Level up: 0%
Activity: 50.7%
Activity: 50.7% Activity: 50.7% Activity: 50.7%
Last Achievements
Award-Showcase
NMR Credits: 0
NMR Points: 193,617
Downloads: 0
Uploads: 0
Default Heteronuclear DNP of 1H and 19F nuclei using BDPA as a polarizing agent #DNPNMR

From The DNP-NMR Blog:

Heteronuclear DNP of 1H and 19F nuclei using BDPA as a polarizing agent #DNPNMR

Gennaro, Antonio, Alexander Karabanov, Alexey Potapov, and Walter Köckenberger. “Heteronuclear DNP of 1H and 19F Nuclei Using BDPA as a Polarizing Agent.” Physical Chemistry Chemical Physics 22, no. 15 (2020): 7803–16.

https://doi.org/10.1039/D0CP00892C.


This work explores the dynamic nuclear polarization (DNP) of 1H and 19F nuclei in a sample of 25/75 (% v/v) fluorobenzene/toluene containing the radical 1,3-bisphenylene-2-phenylallyl radical (BDPA) as a polarizing agent. Previously, heteronuclear effects in DNP were studied by analysing the shapes of DNP spectra, or by observing cross-relaxation between nuclei of different types. In this work, we report a rather specific DNP spectrum, where 1H and 19F nuclei obtain polarizations of opposite signs upon microwave (MW) irradiation. In order to explain this observation, we introduce a novel mechanism called heteronuclear thermal mixing (hn-TM). Within this mechanism the spectra of opposite signs can then be explained due to the presence of four-spin systems, involving a pair of dipolar coupled electron spins and hyperfine coupled nuclear spins of 1H and 19F, such that a condition relating their Larmor frequencies |o1e o2e| E oH oF is satisfied. Under this condition, a strong mixing of electron and nuclear states takes place, enabling simultaneous four-spin flip-flops. Irradiation of electron spin transitions with MW followed by such four-spin flip-flops produces non-equilibrium populations of |aHbFi and |bHaFi states, thus leading to the enhancements of opposite signs for 1H and 19F. Signal enhancements, build-up times and DNP-spectra as a function of MW power and polarizing agent concentration, all provide additional support for assigning the observed DNP mechanism as hn-TM and distinguishing it from other possible mechanisms. We also develop a quantum mechanical model of hn-TM based on averaging of spin Hamiltonians. Simulations based on this model show very good qualitative agreement with experimental data. In addition, the system exhibits cross-relaxation between 1H and 19F induced by the presence of BDPA, which was detected by measuring the 19F signal build-up upon saturation of 1H nuclei with a train of radio-frequency pulses. We demonstrate that such cross-relaxation most likely originates due to the same electron and nuclear states mixing in the four-spin systems.




Go to The DNP-NMR Blog for more info.
Reply With Quote


Did you find this post helpful? Yes | No

Reply
Similar Threads
Thread Thread Starter Forum Replies Last Post
Polarizing Agents: Evolution and Outlook in Free Radical Development for DNP #DNPNMR
From The DNP-NMR Blog: Polarizing Agents: Evolution and Outlook in Free Radical Development for DNP #DNPNMR Casano, Gilles, Hakim Karoui, and Olivier Ouari. “Polarizing Agents: Evolution and Outlook in Free Radical Development for DNP” 7 (2018): 14. https://doi.org/10.1002/9780470034590.emrstm1547.
nmrlearner News from NMR blogs 0 05-27-2020 02:44 PM
A biradical-tagged phospholipid as a polarizing agent for solid-state MAS Dynamic Nuclear Polarization NMR of membrane proteins #DNPNMR
From The DNP-NMR Blog: A biradical-tagged phospholipid as a polarizing agent for solid-state MAS Dynamic Nuclear Polarization NMR of membrane proteins #DNPNMR Good, Daryl B., Maxim A. Voinov, David Bolton, Meaghan E. Ward, Ivan V. Sergeyev, Marc Caporini, Peter Scheffer, et al. “A Biradical-Tagged Phospholipid as a Polarizing Agent for Solid-State MAS Dynamic Nuclear Polarization NMR of Membrane Proteins.” Solid State Nuclear Magnetic Resonance, April 2019, S0926204018301140. https://doi.org/10.1016/j.ssnmr.2019.04.003.
nmrlearner News from NMR blogs 0 05-06-2019 04:47 PM
[NMR paper] A biradical-tagged phospholipid as a polarizing agent for solid-state MAS Dynamic Nuclear Polarization NMR of membrane proteins.
A biradical-tagged phospholipid as a polarizing agent for solid-state MAS Dynamic Nuclear Polarization NMR of membrane proteins. A biradical-tagged phospholipid as a polarizing agent for solid-state MAS Dynamic Nuclear Polarization NMR of membrane proteins. Solid State Nucl Magn Reson. 2019 Apr 17;100:92-101 Authors: Good DB, Voinov MA, Bolton D, Ward ME, Sergeyev IV, Caporini M, Scheffer P, Lo A, Rosay M, Marek A, Brown LS, I Smirnov A, Ladizhansky V Abstract A novel Dynamic Nuclear Polarization (DNP) NMR polarizing agent...
nmrlearner Journal club 0 04-29-2019 11:03 AM
DNP sensitivity of 19F-NMR signals in hexafluorobenzene depending on polarizing agent type #DNPNMR #ODNP
From The DNP-NMR Blog: DNP sensitivity of 19F-NMR signals in hexafluorobenzene depending on polarizing agent type #DNPNMR #ODNP Peksoz, Ahmet. “DNP Sensitivity of 19F-NMR Signals in Hexafluorobenzene Depending on Polarizing Agent Type.” Magnetic Resonance in Chemistry 54, no. 9 (2016): 748–52. https://doi.org/10.1002/mrc.4445.
nmrlearner News from NMR blogs 0 06-19-2018 02:55 AM
Nanodiamond as a New Hyperpolarizing Agent and Its 13C MRS #DNPNMR
From The DNP-NMR Blog: Nanodiamond as a New Hyperpolarizing Agent and Its 13C MRS #DNPNMR Dutta, Prasanta, Gary V. Martinez, and Robert J. Gillies. “Nanodiamond as a New Hyperpolarizing Agent and Its 13C MRS.” The Journal of Physical Chemistry Letters 5, no. 3 (February 6, 2014): 597–600. https://doi.org/10.1021/jz402659t
nmrlearner News from NMR blogs 0 06-07-2018 01:44 AM
Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy #DNPNMR #NMR
From The DNP-NMR Blog: Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy #DNPNMR #NMR Most commonly nitroxide-based radicals are used in DNP. However, there are many other stable radicals. This one is a UV generated radical that is stable for weeks at room temperature. In addition it exhibits a fairly narrow linewidth. This radical, in combination with another narrow line radical (BDPA, trityl, etc.) could make a very efficient polarizing agent when mixed together or even...
nmrlearner News from NMR blogs 0 02-12-2018 05:58 PM
Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy #DNPNMR
From The DNP-NMR Blog: Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy #DNPNMR p.p1 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 12.0px Helvetica} DeHaven, B.A., et al., Persistent Radicals of Self-assembled Benzophenone bis-Urea Macrocycles: Characterization and Application as a Polarizing Agent for Solid-state DNP MAS Spectroscopy. Chemistry, 2017. 23(34): p. 8315-8319. https://www.ncbi.nlm.nih.gov/pubmed/28423212
nmrlearner News from NMR blogs 0 10-05-2017 01:01 AM
TEMPOL as a polarizing agent for dynamic nuclear polarization of aqueous solutions
From The DNP-NMR Blog: TEMPOL as a polarizing agent for dynamic nuclear polarization of aqueous solutions Gafurov, M., TEMPOL as a polarizing agent for dynamic nuclear polarization of aqueous solutions. Magn. Reson. Solids., 2013. 15: p. 13103. http://mrsej.ksu.ru/contents.html#13103
nmrlearner News from NMR blogs 0 05-03-2013 02:26 PM


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



BioNMR advertisements to pay for website hosting and domain registration. Nobody does it for us.



Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright, BioNMR.com, 2003-2013
Search Engine Friendly URLs by vBSEO 3.6.0

All times are GMT. The time now is 01:58 AM.


Map