Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

Abstract

Siderophores are small molecules secreted by microorganisms in order to scavenge iron from the environment. An example is the thiazoline-containing natural product massiliachelin, which is produced by Massilia sp. NR 4-1 under iron-deficient conditions. Based on experimental evidence and genome analysis, it was suspected that this bacterium synthesizes further iron-chelating molecules. After a thorough inspection of its metabolic profile, six previously overlooked compounds were isolated that were active in the chrome azurol S (CAS) assay. Mass spectrometric measurements and nuclear magnetic resonance spectroscopic analyses identified these compounds as possible biosynthetic intermediates or shunt products of massiliachelin. Their bioactivity was tested against one Gram-positive and three Gram-negative bacteria.

Molecular Networking‐Guided Discovery of Kyonggic Acids in Massilia spp.

“…An interesting obervation made during these analyses concerned massiliachelin. In a previous study, it had been demonstrated that the production of this siderophore is accompanied by the formation of a number of biosynthetic shunt products [9] . Nevertheless, massiliachelin was found in a rather small cluster in the feature‐based molecular networking, while the shunt products formed discrete clusters (Figure 5).…”

“…In a previous study, it had been demonstrated that the production of this siderophore is accompanied by the formation of a number of biosynthetic shunt products. [9] Nevertheless, massiliachelin was found in a rather small cluster in the feature-based molecular networking, while the shunt products formed discrete clusters (Figure 5). The different clustering can be explained by distinct fragmentation patterns of these molecules.…”

“…The MS/MS spectra of the depicted molecules were consistent with previously reported data. [8,9] Every circle represents a distinct mass feature. The circle size corresponds to the highest observed abundance of the respective mass feature in LC-MS/MS analysis.…”

“…NR 4-1, which also yielded the thiazoline siderophore massiliachelin. [8,9] To obtain a broader view of the metabolic diversity within the genus, we collected metabolomics data from six Massilia strains and processed this data with the Global Natural Products Social Molecular Networking (GNPS) platform. [10] GNPS utilizes computational algorithms to construct spectral networks, wherein related compounds are grouped based on shared fragmentation patterns observed in tandem mass spectrometry (MS/MS) data.…”

“…The latter two compounds were isolated from a biosynthetically particularly talented strain, Massilia sp. NR 4‐1, which also yielded the thiazoline siderophore massiliachelin [8,9] …”