June 2012
Publication year: 2012 Source:Journal of Magnetic Resonance, Volume 219
Non-uniform weighted sampling (NUWS) is a sampling strategy, related to non-uniform sampling (NUS) in the limit of long acquisition times, in which each indirect increment of a multidimensional spectrum is sampled multiple times according to some weighting function. As the spectrum is fully sampled it can be processed in a conventional manner by the discrete Fourier transform, making the analysis of sensitivity much more straightforward than for NUS data. Previously, 2–3 fold increases in signal-to-noise ratio (SNR) have been reported using NUWS. However, as the sampling schedule acts as a window function, the observed SNR must be compared with uniformly sampled data apodized using the same weighting function. On doing this, we calculate more modest improvements of 10–20% in SNR, and these are verified experimentally for spectra of ?-synuclein and YFP. Nevertheless, we prove that NUWS always improves the sensitivity compared with identically processed uniformly sampled data, and when combined with rapid recycling experiments such as the SOFAST–HMQC, NUWS methods have the potential to make a useful and practical contribution to sensitivity-limited measurements. Graphical abstract
Highlights
? Sensitivity of non-uniform weighted sampling compared with uniform sampling. ? Theoretical expressions derived for NMR sensitivity with variable number of scans. ? ‘Real-world’ improvements in sensitivity calculated and verified experimentally. ? Easily applicable to sensitivity-limited samples.
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Christopher A. Waudby, John Christodoulou</br>
Non-uniform weighted sampling (NUWS) is a sampling strategy, related to non-uniform sampling (NUS) in the limit of long acquisition times, in which each indirect increment of a multidimensional spectrum is sampled multiple times according to some weighting function. As the spectrum is fully sampled it can be processed in a conventional...
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05-01-2012 08:03 PM
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
Signal enhancement for the sensitivity-limited solid state NMR experiments using a continuous, non-uniform acquisition scheme.
Signal enhancement for the sensitivity-limited solid state NMR experiments using a continuous, non-uniform acquisition scheme.
Signal enhancement for the sensitivity-limited solid state NMR experiments using a continuous, non-uniform acquisition scheme.
J Magn Reson. 2011 Aug 30;
Authors: Qiang W
Abstract
We describe a sampling scheme for the two-dimensional (2D) solid state NMR experiments, which can be readily applied to the sensitivity-limited samples. The sampling scheme utilizes continuous, non-uniform sampling profile for the...
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09-21-2011 03:31 PM
Structure of the BamC Two-Domain Protein Obtained by Rosetta with a Limited NMR Data Set.
Structure of the BamC Two-Domain Protein Obtained by Rosetta with a Limited NMR Data Set.
Structure of the BamC Two-Domain Protein Obtained by Rosetta with a Limited NMR Data Set.
J Mol Biol. 2011 May 23;
Authors: Warner LR, Varga K, Lange OF, Baker SL, Baker D, Sousa MC, Pardi A
The CS-RDC-NOE Rosetta program was used to generate the solution structure of a 27-kDa fragment of the Escherichia coli BamC protein from a limited set of NMR data. The BamC protein is a component of the essential five-protein ?-barrel assembly machine in E. coli. The...
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06-01-2011 02:30 PM
[NMR paper] Sampling of protein dynamics in nanosecond time scale by 15N NMR relaxation and self-
Sampling of protein dynamics in nanosecond time scale by 15N NMR relaxation and self-diffusion measurements.
Related Articles Sampling of protein dynamics in nanosecond time scale by 15N NMR relaxation and self-diffusion measurements.
J Biomol Struct Dyn. 1999 Aug;17(1):157-74
Authors: Orekhov VY, Korzhnev DM, Pervushin KV, Hoffmann E, Arseniev AS
This paper presents a procedure for detection of intermediate nanosecond internal dynamics in globular proteins. The procedure uses 1H-15N relaxation measurements at several spectrometer frequencies...
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11-18-2010 08:31 PM
[NMR paper] Analysis of biological fluids using 600 MHz proton NMR spectroscopy: application of h
Analysis of biological fluids using 600 MHz proton NMR spectroscopy: application of homonuclear two-dimensional J-resolved spectroscopy to urine and blood plasma for spectral simplification and assignment.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Analysis of biological fluids using 600 MHz proton NMR spectroscopy: application of homonuclear two-dimensional J-resolved spectroscopy to urine and blood plasma for spectral simplification and assignment.
J Pharm Biomed Anal. 1993...
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08-21-2010 11:53 PM
Tunable paramagnetic relaxation enhancements by [Gd(DPA)3]3â?? for protein structure
Abstract Paramagnetic relaxation enhancements (PRE) present a powerful source of structural information in nuclear magnetic resonance (NMR) studies of proteins and proteinâ??ligand complexes. In contrast to conventional PRE reagents that are covalently attached to the protein, the complex between gadolinium and three dipicolinic acid (DPA) molecules, 3â??, can bind to proteins in a non-covalent yet site-specific manner. This offers straightforward access to PREs that can be scaled by using different ratios of 3â?? to protein, allowing quantitative distance measurements for nuclear spins...
An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR
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