Comparison of 1D and 2D NMR Spectroscopy for Metabolic Profiling

Abstract

High-resolution, liquid state nuclear magnetic resonance (NMR) spectroscopy is a popular platform for metabolic profiling because the technique is nondestructive, quantitative, reproducible, and the spectra contain a wealth of biochemical information. Because of the large dynamic range of metabolite concentrations in biofluids, statistical analyses of one-dimensional (1D) proton NMR data tend to be biased toward selecting changes in more abundant metabolites. Although two-dimensional (2D) proton-proton experiments can alleviate spectral crowding, they have been mainly used for structural determination. In this study, 2D total correlation spectroscopy NMR was used to compare the global metabolic profiles of urine obtained from wild-type and Abcc6-knockout mice. The 2D data were compared to an improved 1D experiment in which signal contributions from macromolecules and the urea peak have been spectroscopically removed for more accurate quantitation of low-abundance metabolites. Although statistical models from both 1D and 2D data could differentiate samples acquired from the two groups of mice, only the 2D spectra allowed the characterization of statistically relevant changes in the low-abundance metabolites. While acquisition of the 2D data require more time, the data obtained resulted in a more meaningful and comprehensive metabolic profile, aided in metabolite identifications, and minimized ambiguities in peak assignments.

Analytical and statistical approaches to metabolomics research

“…The HMBC experiment however has lower sensitivity than the HSQC experiment. A number of investigators have opted for 2-D 1 H -1 H methodologies such as DOSY [80], COSY [81], TOCSY [21], 2-D J-resolved experiments [20], and DQF-COSYiDOSY [82] for better sensitivity and compromised on the limited spectral dispersion of proton.…”

“…Manual pH adjustment using NaOH and HCl is another viable option [19,20]. Based on our own experience, we found that it is best to first adjust the pH with a strong base, NaOH, taking care not to overshoot the desired pH of 7.4, and then add a small amount of phosphate buffer to maintain the pH [21]. For NMR spectral referencing and quantitation, either an internal or external standard is needed.…”

“…Van et al [21] used 2-D total correlation spectroscopy NMR and statistical analysis to compare the global metabolic profiles of urines obtained from wild-type and ABCC6-knockout mice. Three statistical methods were used to analyze the NMR spectra; PCA, PLS-DA, and OPLS-DA.…”

A systems biology approach towards child obesity and obesity-related diseases: integration of clinical, genetic, hormonal and NMR metabonomic factors

“…Signals in a 1D NMR spectrum are assigned to specific metabolic species based on their position in the spectrum, their coupling pattern and relative intensity, along with additional information gained from 2D NMR spectra. 2D NMR methods consist of a series of 1D experiments which are highly useful for reducing the spectral complexity and thus helpful for metabolite assignments (Van et al, 2008). Examples include homonuclear correlation spectroscopy (COSY), J-spectroscopy, total correlation Spectroscopy (TOCSY) and the 2D NOESY experiments.…”

“…Thus 2D NMR spectra are usually solely used for metabolite identification, whereas 1D NMR is usually the method of choice for high-throughput metabolite profiling (Van et al, 2008). …”