Discovery of the Antibiotic Phosacetamycin via a New Mass Spectrometry-Based Method for Phosphonic Acid Detection

Abstract

Naturally occurring phosphonates such as phosphinothricin (Glufosinate, a commercially used herbicide) and fosfomycin (Monurol, a clinically used antibiotic) have proved to be potent and useful biocides. Yet this class of natural products is still an under explored family of secondary metabolites. Discovery of the biosynthetic pathways responsible for the production of these compounds has been simplified by using gene based screening approaches, but detection and identification of the natural products the genes produce has been hampered by a lack of high-throughput methods for screening potential producers under various culture conditions. Here we present an efficient mass-spectrometric method for the selective detection of natural products containing phosphonate and phosphinate functional groups. We have used this method to identify a new phosphonate metabolite, phosacetamycin, whose structure, biological activity, and biosynthetic gene cluster are reported.

Discovery of phosphonic acid natural products by mining the genomes of 10,000 actinomycetes

“…Third, gene-based surveys have proven that phosphonate biosynthesis is relatively common in microorganisms, with the largest reservoir of unexplored pathways observed within Actinobacteria (23). Finally, the carbon-phosphorus bond endows phosphonates with unique chemical properties that enable their chemispecific detection from complex mixtures of metabolites using MS and NMR spectroscopy, even when the structure of the molecule in question is unknown (24,25). These methods facilitate the isolation and characterization of phosphonate natural products by enabling their direct detection during production screening and purification.…”

“…Including the eight additional molecules we recently reported elsewhere (24,38,40,45) (SI Appendix, Fig. S4), this program has yielded 19 new phosphonate natural products to date.…”

Synthesis and Biological Applications of Phosphinates and Derivatives

“…In recent years it has become increasingly apparent that more highly reduced phosphorus compounds (i.e. phosphonic and phosphinic acids) also play prominent roles in life science [245][246][247]. The mechanisms which have driven the chemical evolution of phosphate-based biochemistry are still under discussion [248].…”

Collision-Induced Dissociation Mass Spectrometry: A Powerful Tool for Natural Product Structure Elucidation

“…57 Related compounds within a sample are most often found by identifying a characteristic fragment or neutral loss (NL) of the unknown and performing an additional analysis of the sample, searching for molecules with similar fragments or losses (Level 6, Table 2). 48,58 The criteria for 'similar' will depend on the goals of the analysis, sometimes requiring three or more shared fragments/NLs to ensure a high degree of structural similarity, or for more marginally-related compounds, one similar fragment/NL may be adequate, especially in the case that it is an uncommon 7 ion/NL (i.e, the loss of H 2 O is unlikely to be helpful in identifying similar structures). It is also useful to include in subsequent analyses adducts and different charge states of the unknown, if present.…”