Customized metabolomics database for the analysis of NMR ¹H-¹H TOCSY and ¹³C-¹H HSQC-TOCSY spectra of complex mixtures.

Abstract

A customized metabolomics NMR database, termed 1H(13C)-TOCCATA, is introduced, which contains complete 1H and 13C chemical shift information on individual spin systems and isomeric states of common metabolites. Since this information directly corresponds to cross sections of 2D 1H–1H TOCSY and 2D 13C–1H HSQC-TOCSY spectra, it allows the straightforward and unambiguous identification of metabolites of complex metabolic mixtures at 13C natural abundance from these types of experiments. The 1H(13C)-TOCCATA database, which is complementary to the previously introduced TOCCATA database for the analysis of uniformly 13C-labeled compounds, currently contains 455 metabolites, and it can be used through a publicly accessible web portal. We demonstrate its performance by applying it to 2D 1H–1H TOCSY and 2D 13C–1H HSQC-TOCSY spectra of a cell lysate from E. coli, which yields a substantial improvement over other databases, as well as 1D NMR-based approaches, in the number of compounds that can be correctly identified with high confidence.