Abstract
A customized metabolomics NMR database, termed (1)H((13)C)-TOCCATA, is introduced, which contains complete (1)H and (13)C chemical shift information on individual spin systems and isomeric states of common metabolites. Since this information directly corresponds to cross sections of 2D (1)H-(1)H TOCSY and 2D (13)C-(1)H HSQC-TOCSY spectra, it allows the straightforward and unambiguous identification of metabolites of complex metabolic mixtures at (13)C natural abundance from these types of experiments. The (1)H((13)C)-TOCCATA database, which is complementary to the previously introduced TOCCATA database for the analysis of uniformly (13)C-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 (1)H-(1)H TOCSY and 2D (13)C-(1)H 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.