Six- and seven-dimensional experiments by combination of sparse random sampling and projection spectroscopy dedicated for backbone resonance assignment of intrinsically disordered proteins

Abstract

Two novel six- and seven-dimensional NMR experiments are proposed. The new experiments employ non-uniform sampling that enables achieving high resolution in four indirectly detected dimensions and synchronous sampling in the additional dimensions using projection spectroscopy principle. The resulted data sets could be processed as five-dimensional data using existing software. The experiments facilitate resonance assignment of intrinsically disordered proteins. The novel experiments were successfully tested using 1 mM sample of α-synuclein on 600 and 800 MHz NMR spectrometers equipped with standard room temperature probes. The experiments allowed backbone assignment from a 1-day acquisition.

Focusing on “the important” through targeted NMR experiments: an example of selective13C–12C bond detection in complex mixtures

“…7 On extrapolation to 7D NMR, which has recently been demonstrated on disordered proteins via sparse sampling approaches, the peak capacity can potentially reach on the order of 10 18 . [8][9][10] Of course, in most environmental and biological samples, the limiting factor is a lack of sensitivity when dispersing signals into a larger number of higher dimensions. However, as NMR sensitivity continues to increase and sparse sampling approaches improve, 11 NMR experiments of high dimensionality become more feasible, and will therefore likely become central to the next generation of complex mixture research.…”

XLSY: Extra‐Large NMR Spectroscopy

“…The best algorithms for reconstructing spectra from NUS data are impractical for large data sets owing to unbearable computational and storage requirements. Existing methods for spectra with five dimensions require a three‐dimensional reference spectrum or peak list whereas six‐ and seven‐dimensional spectra are produced only as their reduced dimensionality projections . A possible solution for the large data sets may be found in the family of parametric algorithms, although no examples of spectra reconstructions with more than four dimensions have been presented so far.…”

The Nearest-Neighbor Effect on Random-Coil NMR Chemical Shifts Demonstrated Using a Low-Complexity Amino-Acid Sequence

“…In these molecules however, the variability of the chemical shift is much lower because of the similarity of the atoms' chemical environment. Nevertheless, modern NMR spectrometers and multi-dimensional NMR techniques can be used to assign chemical shifts to each (NMR-sensitive) atom in the chain [12][13][14]. The secondary chemical shift then reveals the conformational propensity of a given segment or the presence of residual or transiently populated structure [15].…”