Identification of metabolites and computer-assisted structure elucidations

The new Orbitrap and UPLC system opened many possibilities in the area of metabolomic and natural product identification. The ultrahigh-pressure chromatography has increased the resolving power of chromatography, and Orbitrap mass accuracy has made the determination of molecular composition of precursor and fragment ions straightforward. Together with NMR data structural proposals could be easily made. From the recent publications we can mention the identification of a number of glucosinolate break-down products found to be significant players in plant innate immunity (Bednarek et al. 2009 Science).

Recently, several antibiotics produced by symbiotic streptomycetes in beewolf antennae were identified, and their biological activity was elucidated in cooperation with the Hans Knöll Institute on the campus (Kroiß et al. 2010 Nature Chem. Biol.). The mixture of antibiotics protects beewolf cocoons buried underground for many months against infections, and the molecular basis of this protection in the natural context (without an external bacterial cultivation) was elucidated.

To further harvest the potential of accurate mass data, a cooperation with Prof. S. Böcker (FSU Jena) was initiated to develop software for computer-assisted elucidation of tandem mass spectra. Our first paper is under review and several are in preparation. If successfully completed, this program should help non-specialized scientists to get analyzed compounds classified according to their structural similarity and so revolutionize the field of natural product identification. In the future this program is planned to be linked with spectral databases to enhance the identification power.