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. © 2014 American Chemical Society.