Mechanism of dilute-spin-exchange in solid-state NMR.
J Chem Phys. 2014 Mar 28;140(12):124201
Authors: Lu GJ, Opella SJ
Abstract
In the stationary, aligned samples used in oriented sample (OS) solid-state NMR, (1)H-(1)H homonuclear dipolar couplings are not attenuated as they are in magic angle spinning solid-state NMR; consequently, they are available for participation in dipolar coupling-based spin-exchange processes. Here we describe analytically the pathways of (15)N-(15)N spin-exchange mediated by (1)H-(1)H homonuclear dipolar couplings. The mixed-order proton-relay mechanism can be differentiated from the third spin assisted recoupling mechanism by setting the (1)H to an off-resonance frequency so that it is at the "magic angle" during the spin-exchange interval in the experiment, since the "magic angle" irradiation nearly quenches the former but only slightly attenuates the latter. Experimental spectra from a single crystal of N-acetyl leucine confirm that this proton-relay mechanism plays the dominant role in (15)N-(15)N dilute-spin-exchange in OS solid-state NMR in crystalline samples. Remarkably, the "forbidden" spin-exchange condition under "magic angle" irradiation results in (15)N-(15)N cross-peaks intensities that are comparable to those observed with on-resonance irradiation in applications to proteins. The mechanism of the proton relay in dilute-spin-exchange is crucial for the design of polarization transfer experiments.
[NMR paper] Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
Related Articles Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: Relaxing selective polarization transfer condition between two dilute spins.
J Magn Reson. 2014 Mar 16;242C:214-219
Authors: Zhang Z, Fu R, Li J, Yang J
Abstract
Double cross polarization (DCP) has been widely used for heteronuclear polarization transfer between (13)C...
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Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: relaxing selective polarization transfer condition between two dilute spins
Asymmetric simultaneous phase-inversion cross-polarization in solid-state MAS NMR: relaxing selective polarization transfer condition between two dilute spins
Publication date: Available online 16 March 2014
Source:Journal of Magnetic Resonance</br>
Author(s): Zhengfeng Zhang , Riqiang Fu , Jianping Li , Jun Yang</br>
Double cross polarization (DCP) has been widely used for heteronuclear polarization transfer between 13C and 15N in solid-state magic-angle spinning (MAS) NMR. However, DCP is such sensitive to experimental settings that small variations or...
[NMR paper] Investigation of the mechanism of action of novel amphipathic peptides: Insights from solid-state NMR studies of oriented lipid bilayers.
Investigation of the mechanism of action of novel amphipathic peptides: Insights from solid-state NMR studies of oriented lipid bilayers.
Related Articles Investigation of the mechanism of action of novel amphipathic peptides: Insights from solid-state NMR studies of oriented lipid bilayers.
Biochim Biophys Acta. 2014 Feb 6;
Authors: Fillion M, Noël M, Lorin A, Voyer N, Auger M
Abstract
We have investigated in the present study the effect of both non-selective and selective cationic 14-mer peptides on the lipid orientation of DMPC bilayers...
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02-11-2014 09:58 PM
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Zhengfeng Zhang, Yimin Miao, Xiaoli Liu, Jun Yang, Conggang Li, Feng Deng, Riqiang Fu</br>
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N->C cross polarization, the 13C RF amplitude is...
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03-09-2012 09:16 AM
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Dual-band Selective Double Cross Polarization for Heteronuclear Polarization Transfer between Dilute Spins in Solid-State MAS NMR
Publication year: 2012
Source: Journal of Magnetic Resonance, Available online 5 March 2012</br>
Zhengfeng*Zhang, Yimin*Miao, Xiaoli*Liu, Jun*Yang, Conggang*Li, ...</br>
A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N->C cross polarization, theC RF amplitude is modulated...
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03-06-2012 06:04 AM
Challenges in numerical simulations of solid-state NMR experiments: Spin exchange pulse sequences.
Challenges in numerical simulations of solid-state NMR experiments: Spin exchange pulse sequences.
Challenges in numerical simulations of solid-state NMR experiments: Spin exchange pulse sequences.
Solid State Nucl Magn Reson. 2011 Feb 1;
Authors: Vosegaard T
While simulations are essential for interpretation of solid-state NMR experiments, large spin systems involved in e.g. spin-diffusion experiments and/or dynamic effects like chemical exchange pose great challenges for the numerical simulations, where we typically want to include effects of...
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[NMR paper] Solid-state NMR studies of the mechanism of the opsin shift in the visual pigment rho
Solid-state NMR studies of the mechanism of the opsin shift in the visual pigment rhodopsin.
Related Articles Solid-state NMR studies of the mechanism of the opsin shift in the visual pigment rhodopsin.
Biochemistry. 1990 Sep 4;29(35):8158-64
Authors: Smith SO, Palings I, Miley ME, Courtin J, de Groot H, Lugtenburg J, Mathies RA, Griffin RG
Solid-state 13C NMR spectra have been obtained of bovine rhodopsin and isorhodopsin regenerated with retinal selectively 13C labeled along the polyene chain. In rhodopsin, the chemical shifts for 13C-5,...