[NMR paper] CW dipolar broadening EPR spectroscopy and mechanically aligned bilayers used to measure distance and relative orientation between two TOAC spin labels on an antimicrobial peptide
CW dipolar broadening EPR spectroscopy and mechanically aligned bilayers used to measure distance and relative orientation between two TOAC spin labels on an antimicrobial peptide
Publication date: December 2014 Source:Journal of Magnetic Resonance, Volume 249
Author(s): Indra D. Sahu , Eric J. Hustedt , Harishchandra Ghimire , Johnson J. Inbaraj , Robert M. McCarrick , Gary A. Lorigan
An EPR membrane alignment technique was applied to measure distance and relative orientations between two spin labels on a protein oriented along the surface of the membrane. Previously we demonstrated an EPR membrane alignment technique for measuring distances and relative orientations between two spin labels using a dual TOAC-labeled integral transmembrane peptide (M2? segment of Acetylcholine receptor) as a test system. In this study we further utilized this technique and successfully measured the distance and relative orientations between two spin labels on a membrane peripheral peptide (antimicrobial peptide magainin-2). The TOAC-labeled magainin-2 peptides were mechanically aligned using DMPC lipids on a planar quartz support, and CW-EPR spectra were recorded at specific orientations. Global analysis in combination with rigorous spectral simulation was used to simultaneously analyze data from two different sample orientations for both single- and double-labeled peptides. We measured an internitroxide distance of 15.3Å from a dual TOAC-labeled magainin-2 peptide at positions 8 and 14 that closely matches with the 13.3Å distance obtained from a model of the labeled magainin peptide. In addition, the angles determining the relative orientations of the two nitroxides have been determined, and the results compare favorably with molecular modeling. This study demonstrates the utility of the technique for proteins oriented along the surface of the membrane in addition to the previous results for proteins situated within the membrane bilayer. Graphical abstract
DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature
From The DNP-NMR Blog:
DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature
Jakdetchai, O., et al., DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature. J Am Chem Soc, 2014.
http://www.ncbi.nlm.nih.gov/pubmed/25333422
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10-24-2014 07:18 PM
[NMR paper] DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature.
DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature.
Related Articles DNP-enhanced NMR on aligned Lipid Bilayers at ambient Temperature.
J Am Chem Soc. 2014 Oct 21;
Authors: Jakdetchai O, Denysenkov V, Becker-Baldus J, Dutagaci B, Prisner T, Glaubitz C
Abstract
DNP-enhanced solid-state NMR has been shown to hold great potential for functional studies of membrane proteins at low temperatures due to its great sensitivity improvement. There are however numerous applications, for which experiments at ambient temperature...
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10-22-2014 12:34 PM
[NMR paper] Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of rotationally aligned membrane proteins in phospholipid bilayers.
Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of rotationally aligned membrane proteins in phospholipid bilayers.
Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of rotationally aligned membrane proteins in phospholipid bilayers.
J Magn Reson. 2014 Mar 1;242C:224-232
Authors: Das BB, Zhang H, Opella SJ
Abstract
A method for making resonance assignments in magic angle spinning solid-state NMR spectra of membrane proteins that utilizes the range of heteronuclear dipolar coupling...
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04-06-2014 02:01 AM
Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of Rotationally Aligned Membrane Proteins in Phospholipid Bilayers
Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of Rotationally Aligned Membrane Proteins in Phospholipid Bilayers
Publication date: Available online 1 March 2014
Source:Journal of Magnetic Resonance</br>
Author(s): Bibhuti B. Das , Hua Zhang , Stanley J. Opella</br>
A method for making resonance assignments in magic angle spinning solid-state NMR spectra of membrane proteins that utilizes the range of hetero-nuclear dipolar coupling frequencies in combination with conventional chemical shift based assignment methods is demonstrated. The...
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03-01-2014 11:11 AM
Intermediate Dipolar Distances from Spin Labels
Intermediate Dipolar Distances from Spin Labels
Publication date: Available online 16 November 2013
Source:Journal of Magnetic Resonance</br>
Author(s): Derek Marsh</br>
Methods for determining inter-spin distances between nitroxide spin labels from dipolar couplings in the intermediate range (r 12 ? 1.1-2 nm) by CW-EPR are addressed. For nitroxide powder patterns, the assumption of unlike spins is a better approximation than assuming strong coupling between like spins. Methods that determine the average splitting in dipolar deconvolutions yield the mean value ?...
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11-17-2013 07:00 AM
Conformational dynamics and distribution of nitroxide spin labels
Conformational dynamics and distribution of nitroxide spin labels
Publication date: Available online 18 April 2013
Source:Progress in Nuclear Magnetic Resonance Spectroscopy</br>
Author(s): Gunnar Jeschke</br>
Long-range distance measurements based on paramagnetic relaxation enhancement (PRE) in NMR, quantification of surface water dynamics near biomacromolecules by Overhauser dynamic nuclear polarization (DNP) and sensitivity enhancement by solid-state DNP all depend on introducing paramagnetic species into an otherwise diamagnetic NMR sample. The species can be...
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04-18-2013 10:12 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...