Repetitive cross-polarization contacts via equilibration-re-equilibration of the proton bath: sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles
Repetitive cross-polarization contacts via equilibration-re-equilibration of the proton bath: sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles
Publication year: 2011 Source: Journal of Magnetic Resonance, In Press, Accepted Manuscript, Available online 2 July 2011
Wenxing, Tang , Alexander A., Nevzorov
Thermodynamic limit of magnetization corresponding to the intact proton bath often cannot be transferred in a single cross-polarization contact. This is mainly due to the finite ratio between the number densities of the high- and low-gamma nuclei, quantum-mechanical bounds on spin dynamics, and Hartmann-Hahn mismatches due to rf field inhomogeneity. Moreover, for fully hydrated membrane proteins refolded in magnetically oriented bicelles, short spin-lock relaxation times (T1?) and rf heating can further decrease cross polarization efficiency. Here we show that multiple equilibrations-re-equilibrations of the high- and low-spin reservoirs during the preparation period yield an over two-fold gain in the magnetization transfer... Graphical abstract
*Graphical abstract:**Highlights:*? Cross-polarization (CP) cannot be fully transferred in a single contact for membrane proteins refolded in bicelles. ? This is due to thermodynamic and quantum mechanical bounds, as well as Hartmann-Hahn mismatches. ? The new REP-CP sequence yields a two-fold gain for bicelle-reconstituted proteins as compared to a single CP. ? The gain is achieved by employing the differences between T1 relaxation times for the high and low spins.
Rapid Solid-State NMR of Deuterated Proteins by Interleaved Cross-Polarization fromH andH Nuclei
Rapid Solid-State NMR of Deuterated Proteins by Interleaved Cross-Polarization fromH andH Nuclei
Publication year: 2011
Source: Journal of Magnetic Resonance, Available online 9 November 2011</br>
Morten*Bjerring, Berit*Paaske, Hartmut*Oschkinat, Umit*Akbey, Niels Chr.*Nielsen</br>
We present a novel sampling strategy, interleaving acquisition of multiple NMR spectra by exploiting initial polarization subsequently fromH andH spins, taking advantage of their differentT1relaxation times. DifferentH- andH-polarization based spectra are in this way simultaneously recorded improving either...
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Paramagnetic relaxation enhancement to improve sensitivity of fast NMR methods: application to intrinsically disordered proteins
Paramagnetic relaxation enhancement to improve sensitivity of fast NMR methods: application to intrinsically disordered proteins
Abstract We report enhanced sensitivity NMR measurements of intrinsically disordered proteins in the presence of paramagnetic relaxation enhancement (PRE) agents such as Ni2+-chelated DO2A. In proton-detected 1H-15N SOFAST-HMQC and carbon-detected (H-flip)13CO-15N experiments, faster longitudinal relaxation enables the usage of even shorter interscan delays. This results in higher NMR signal intensities per units of experimental time, without adverse line...
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10-21-2011 10:04 PM
Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers
Multidimensional oriented solid-state NMR experiments enable the sequential assignment of uniformly 15N labeled integral membrane proteins in magnetically aligned lipid bilayers
Abstract Oriented solid-state NMR is the most direct methodology to obtain the orientation of membrane proteins with respect to the lipid bilayer. The method consists of measuring 1H-15N dipolar couplings (DC) and 15N anisotropic chemical shifts (CSA) for membrane proteins that are uniformly aligned with respect to the membrane bilayer. A significant advantage of this approach is that tilt and azimuthal...
[NMR paper] High-resolution NMR spectroscopy of membrane proteins in aligned bicelles.
High-resolution NMR spectroscopy of membrane proteins in aligned bicelles.
Related Articles High-resolution NMR spectroscopy of membrane proteins in aligned bicelles.
J Am Chem Soc. 2004 Dec 1;126(47):15340-1
Authors: De Angelis AA, Nevzorov AA, Park SH, Howell SC, Mrse AA, Opella SJ
High-resolution solid-state NMR spectra can be obtained from uniformly (15)N-labeled membrane proteins in magnetically aligned bicelles. Fast uniaxial diffusion about the axis of the bilayer normal results in single-line spectra that contain the orientational...
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11-24-2010 10:03 PM
[NMR paper] NMR solution structure determination of membrane proteins reconstituted in detergent
NMR solution structure determination of membrane proteins reconstituted in detergent micelles.
Related Articles NMR solution structure determination of membrane proteins reconstituted in detergent micelles.
FEBS Lett. 2003 Nov 27;555(1):144-50
Authors: Fernández C, Wüthrich K
As an alternative to X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy in solution can be used for three-dimensional structure determination of small membrane proteins, preferably proteins with beta-barrel fold. This paper reviews recent achievements as...
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11-24-2010 09:16 PM
Mechanically, Magnetically, and "Rotationally Aligned" Membrane Proteins in Phospholi
Mechanically, Magnetically, and "Rotationally Aligned" Membrane Proteins in Phospholipid Bilayers Give Equivalent Angular Constraints for NMR Structure Determination.
Related Articles Mechanically, Magnetically, and "Rotationally Aligned" Membrane Proteins in Phospholipid Bilayers Give Equivalent Angular Constraints for NMR Structure Determination.
J Phys Chem B. 2010 Oct 20;
Authors: Park SH, Das BB, De Angelis AA, Scrima M, Opella SJ
The native environment for membrane proteins is the highly asymmetric phospholipid bilayer, and this has a large...
Repetitive cross-polarization contacts via equilibration-re-equilibration of the proton bath: sensitivity enhancement for NMR of membrane proteins reconstituted in magnetically aligned bicelles
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