Dereplication ofStreptomycessp. AMC 23 polyether ionophore antibiotics by accurate-mass electrospray tandem mass spectrometry

Abstract

Actinomycetes, especially those belonging to the genus Streptomyces, are economically important from a biotechnological standpoint: they produce antibiotics, anticancer compounds and a variety of bioactive substances that are potentially applicable in the agrochemical and pharmaceutical industries. This paper combined accurate-mass electrospray tandem mass spectrometry in the full scan and product ion scan modes with compounds library data to identify the major compounds in the crude extract produced by Streptomyces sp. AMC 23; it also investigated how sodiated nonactin ([M + Na](+)) fragmented. Most product ions resulted from elimination of 184 mass units due to consecutive McLafferty-type rearrangements. The data allowed identification of four macrotetrolides homologous to nonactin (monactin, isodinactin, isotrinactin/trinactin and tetranactin) as well as three related linear dimer compounds (nonactyl nonactoate, nonactyl homononactoate and homononactyl homononactoate). The major product ions of the sodiated molecules of these compounds also originated from elimination of 184 and 198 mass units. UPLC-MS/MS in the neutral loss scan mode helped to identify these compounds on the basis of the elimination of 184 and 198 mass units. This method aided monitoring of the relative production of these compounds for 32 days and revealed that the biosynthetic process began with increased production of linear dimers as compared with macrotetrolides. These data could facilitate dereplication and identification of these compounds in other microbial crude extracts.

Fragmentation reactions using electrospray ionization mass spectrometry: an important tool for the structural elucidation and characterization of synthetic and natural products

“…12a). 93,95 Li and co-workers reported the occurrence of McLafferty-type hydrogen rearrangements for the elimination of the prenyl chain from prenylated furanocoumarins. 87 In Fig.…”

Fragmentation of 2‐aroylbenzofuran derivatives by electrospray ionization tandem mass spectrometry

“…Moreover, tandem mass spectrometry (MS/MS) has allowed scientists to study, understand, and control some aspects of gas‐phase ion chemistry . Currently, ESI‐MS/MS has been used to investigate an increasing number of classes of synthetic and natural products . The resulting data have helped to feed the literature and to identify the structure of these compounds and their metabolites in complex mixtures by liquid chromatography tandem mass spectrometry (LC‐MS/MS) .…”

Enhanced Production and Quantitative Evaluation of Nigericin from the Algerian Soil-Living Streptomyces youssoufiensis SF10 Strain

“…Considerable efforts have been undertaken in recent years to develop accurate and sensitive methods for the characterization and quantification of ionophoric compounds [27] and a number of analyses have been specifically performed on nigericin using the LC-MS technique [14]. In order to quantitatively detect the nigericin amount present in crude extracts obtained from the strain grown under different culture conditions, we developed a method based on the use of a chromatographic system equipped with an ELSD.…”