Adding a diazo-transfer reagent to culture to generate secondary metabolite probes for click chemistry

Converting discrete microbial metabolites into chemical probes for chemical biology and medicinal chemistry studies is typically preceded by lengthy purification and chemical derivatization processes. Standard practice involves purifying the target microbial metabolite from culture, followed by derivatization and/or conjugation chemistry to convert the pure metabolite into a tagged species. This multistep approach can pose difficulties in generating useful yields of chemical probes, particularly in the case of low-abundant metabolites, as common in metabolomes. This chapter describes a methodological approach to simplify the steps towards generating chemical probes from complex mixtures, that combines: (a) tailored purification processes; (b) compound identification using state-of-the-art tandem mass spectrometry and data-dependent fragmentation; and (c) in situ bioorthogonal bioconjugation chemistries. The combination of these methods, as illustrated by the conversion of a set of amine-bearing metabolites to the cognate azide analogs suitable for biotinylation through azide-alkyne cycloaddition, describes a powerful approach to access new chemical probes of low-abundant metabolites that might otherwise be inaccessible using traditional methods.