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J Magn Reson. 2012 Jun;219:46-52. doi: 10.1016/j.jmr.2012.04.013. Epub 2012 May 1.

An analysis of NMR sensitivity enhancements obtained using non-uniform weighted sampling, and the application to protein NMR.

Author information

1
Institute of Structural and Molecular Biology, University College London and Birkbeck College, London WC1E 6BT, UK. c.waudby@ucl.ac.uk

Abstract

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 α-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.

PMID:
22609525
DOI:
10.1016/j.jmr.2012.04.013
[Indexed for MEDLINE]

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