NMR spectroscopy is a powerful method in structural and functional analysis of macromolecules and has become particularly prevalent in studies of protein structure, function and dynamics. Unique to NMR spectroscopy is the relatively low constraints on sample preparation and the high level of control of sample conditions. Proteins can be studied in a wide range of buffer conditions, e.g. different pHs and variable temperatures, allowing studies of proteins under conditions that are closer to their native environment compared to other structural methods such as X-ray crystallography and electron microscopy. The key disadvantage of NMR is the relatively low sensitivity of the method, requiring either concentrated samples or very lengthy data-acquisition times. Thus, proteins that are unstable or can only be studied in dilute solutions are often considered practically unfeasible for NMR studies. Here, we describe a general method, where non-uniform sampling (NUS) allows for signal averaging to be monitored in an iterative manner, enabling efficient use of spectrometer time, ultimately leading to savings in costs associated with instrument and isotope-labelled protein use. The method requires preparation of multiple aliquots of the protein sample that are flash-frozen and thawed just before acquisition of a short NMR experiments carried out while the protein is stable (12Â*h in the presented case). Non-uniform sampling enables sufficient resolution to be acquired for each short experiment. Identical NMR datasets are acquired and sensitivity is monitored after each co-added spectrum is reconstructed. The procedure is repeated until sufficient signal-to-noise is obtained. We discuss how maximum entropy reconstruction is used to process the data, and propose a variation on the previously described method of automated parameter selection. We conclude that combining NUS with iterative co-addition is a general approach, and particularly powerful when applied to unstable proteins.
[U. of Ottawa NMR Facility Blog] Non-uniform Sampling (NUS)
Non-uniform Sampling (NUS)
Collecting 2D or 3D NMR data can be very time consuming. The indirect dimension of a 2D experiment is sampled linearly via the t1 increments in the pulse sequence. An FID must be collected for every single linearly spaced t1 increment. In the interest in collecting 2D or 3D NMR data in a more time efficient manner, a great deal of effort is made towards faster data collection techniques. While some of these methods are based on spatial selectivity, others are based on sparse sampling techniques in the indirect dimensions of nD NMR sequences. One such sparse...
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05-11-2016 08:04 PM
[NMR paper] Non-uniform sampling of NMR relaxation data.
Non-uniform sampling of NMR relaxation data.
Related Articles Non-uniform sampling of NMR relaxation data.
J Biomol NMR. 2016 Feb 4;
Authors: Linnet TE, Teilum K
Abstract
The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors in the extracted dynamic parameters. By systematic reducing the coverage...
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02-06-2016 03:10 PM
Non-uniform sampling of NMR relaxation data
Non-uniform sampling of NMR relaxation data
Abstract
The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors in the extracted dynamic parameters. By systematic reducing the coverage of the Nyquist grid of 15N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion datasets for four different proteins and performing a full...
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Journal club
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02-05-2016 02:38 PM
[NMR paper] Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Related Articles Non-Uniform Sampling and J-UNIO Automation for Efficient Protein NMR Structure Determination.
Chemistry. 2015 Jul 28;
Authors: Didenko T, Proudfoot A, Dutta SK, Serrano P, Wüthrich K
Abstract
High-resolution structure determination of small proteins in solution is one of the big assets of NMR spectroscopy in structural biology. Improvements in the efficiency of NMR structure determination by advances in NMR experiments...
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08-02-2015 07:10 AM
[NMR paper] Time-resolved multidimensional NMR with non-uniform sampling.
Time-resolved multidimensional NMR with non-uniform sampling.
Time-resolved multidimensional NMR with non-uniform sampling.
J Biomol NMR. 2014 Jan 17;
Authors: Mayzel M, Rosenlöw J, Isaksson L, Orekhov VY
Abstract
Time-resolved experiments demand high resolution both in spectral dimensions and in time of the studied kinetic process. The latter requirement traditionally prohibits applications of the multidimensional experiments, which, although capable of providing invaluable information about structure and dynamics and almost unlimited...
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01-18-2014 11:31 AM
[NMR analysis blog] Non Uniform Sampling (NUS) NMR Processing
Non Uniform Sampling (NUS) NMR Processing
Background
In the last few years, Non-Uniform Sampling (NUS) has emerged as a very powerful tool to significantly speed up the acquisition of multidimensional NMR experiments due to the fact that only a subset of the usual linearly sampled data in the Nyquist grid is measured.
Unfortunately, this fast acquisition modality introduces a new challenge as the normal Fourier Transform will fail and consequently, special processing techniques are required.
A number of sophisticated methods have been proposed for reconstructing sparsely sampled 2D...
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12-21-2013 03:15 PM
Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment
Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment
Abstract Overexpression of isotope-labeled multi-spanning eukaryotic membrane proteins for structural NMR studies is often challenging. On the one hand, difficulties with achieving proper folding, membrane insertion, and native-like post-translational modifications frequently disqualify bacterial expression systems. On the other hand, eukaryotic cell cultures can be prohibitively expensive. One of the viable alternatives,...
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Proteins
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01-22-2011 03:46 AM
Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment.
Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment.
Uniform isotope labeling of a eukaryotic seven-transmembrane helical protein in yeast enables high-resolution solid-state NMR studies in the lipid environment.
J Biomol NMR. 2011 Jan 19;
Authors: Fan Y, Shi L, Ladizhansky V, Brown LS
Overexpression of isotope-labeled multi-spanning eukaryotic membrane proteins for structural NMR studies is often challenging. On the one hand, difficulties...
A non-uniform sampling approach enables studies of dilute and unstable proteins
Linear Mode
