Related ArticlesMechanically, 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 effect on both their structure and dynamics. Reproducing this environment in samples suitable for spectroscopic and diffraction experiments is a key issue, and flexibility in sample preparation is essential to accommodate the diverse size, shape, and other physical properties of membrane proteins. In most cases, to ensure that the biological activities are maintained, this means reconstituting the proteins in fully hydrated planar phospholipid bilayers. The asymmetric character of protein-containing bilayers means that it is possible to prepare either oriented or unoriented (powder) samples. Here we demonstrate the equivalence of mechanical, magnetic, and what we refer to as "rotational alignment" of membrane proteins in phospholipid bilayer samples for solid-state NMR spectroscopy. The trans-membrane domain of virus protein "u" (Vpu) from human immunodeficiency virus (HIV-1) and the full-length membrane-bound form of fd bacteriophage coat protein in phospholipid bilayers are used as examples. The equivalence of structural constraints from oriented and unoriented (powder) samples of membrane proteins is based on two concepts: (1) their alignment is defined by the direction of the bilayer normal relative to the magnetic field and (2) they undergo rapid rotational diffusion about the same bilayer normal in liquid crystalline membranes. The measurement of angular constraints relative to a common external axis system defined by the bilayer normal for all sites in the protein is an essential element of oriented sample (OS) solid-state NMR.
PMID: 20961141 [PubMed - as supplied by publisher]
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...
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</br>
Wenxing, Tang , Alexander A., Nevzorov</br>
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-...
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Detecting the "Afterglow" of (13)C NMR in Proteins Using Multiple Receivers.
Detecting the "Afterglow" of (13)C NMR in Proteins Using Multiple Receivers.
Related Articles Detecting the "Afterglow" of (13)C NMR in Proteins Using Multiple Receivers.
J Am Chem Soc. 2010 Dec 2;
Authors: Kupc?e E, Kay LE, Freeman R
We show that the weak signal that remains after (13)C-detected experiments (the (13)C "afterglow") can still be measured with high sensitivity by proton detection. This is illustrated by the incorporation of two experiments, 2D (HA)CACO and 3D (HA)CA(CO)NNH, into a single pulse sequence that makes use of two receivers...
[NMR paper] NMR experiments on aligned samples of membrane proteins.
NMR experiments on aligned samples of membrane proteins.
Related Articles NMR experiments on aligned samples of membrane proteins.
Methods Enzymol. 2005;394:350-82
Authors: De Angelis AA, Jones DH, Grant CV, Park SH, Mesleh MF, Opella SJ
NMR methods can be used to determine the structures of membrane proteins. Lipids can be chosen so that protein-containing micelles, bicelles, or bilayers are available as samples. All three types of samples can be aligned weakly or strongly, depending on their rotational correlation time. Solution NMR methods...
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11-24-2010 11:14 PM
[NMR paper] Lanthanide ions bind specifically to an added "EF-hand" and orient a membrane protein
Lanthanide ions bind specifically to an added "EF-hand" and orient a membrane protein in micelles for solution NMR spectroscopy.
Related Articles Lanthanide ions bind specifically to an added "EF-hand" and orient a membrane protein in micelles for solution NMR spectroscopy.
J Magn Reson. 2000 Oct;146(2):381-4
Authors: Ma C, Opella SJ
Twelve amino acid residues corresponding to an "EF-hand" calcium-binding site were added to the N-terminus of a protein, providing a specific lanthanide ion binding that weakly orients the protein in solution. A...
Mechanically, Magnetically, and "Rotationally Aligned" Membrane Proteins in Phospholi
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