Salimabromide is an antibiotic polyketide that was previously isolated from the obligate marine myxobacterium Enhygromyxa salina, and its densely functionalized and conformationally rigid tetracyclic framework is unprecedented in nature. Herein we report the first chemical synthesis of the target structure by employing a series of well-orchestrated, robust transformations, highlighted by an acid-promoted, powerful Wagner-Meerwein rearrangement/Friedel-Crafts cyclization sequence to forge the two adjacent quaternary carbon centers embedded in the tetrahydronaphthalene. A high-yielding ketiminium mediated [2+2]-cycloaddition was also utilized for the simultaneous construction of the remaining three stereocenters.
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http://dx.doi.org/10.1021/jacs.8b06228 | DOI Listing |
J Agric Food Chem
November 2024
Department of Chemistry, Chonnam National University, Gwangju 61186, Republic of Korea.
Iron-dependent lipoxygenases (LOXs) are involved in the synthesis of oxylipins from polyunsaturated fatty acids. However, they are usually difficult to overexpress in functional form in microbial cell factories. Moreover, 9-LOXs, generating 9-hydroperoxy fatty acids from C18 polyunsaturated fatty acids, have rarely been found from microbial sources.
View Article and Find Full Text PDFNat Commun
May 2023
Department of Earth System Science, Stanford University, Stanford, CA, 94305, USA.
Eukaryotes produce highly modified sterols, including cholesterol, essential to eukaryotic physiology. Although few bacterial species are known to produce sterols, de novo production of cholesterol or other complex sterols in bacteria has not been reported. Here, we show that the marine myxobacterium Enhygromyxa salina produces cholesterol and provide evidence for further downstream modifications.
View Article and Find Full Text PDFMar Drugs
January 2022
Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8 1, 66123 Saarbrücken, Germany.
Marine myxobacteria present a virtually unexploited reservoir for the discovery of natural products with diverse biological functions and novel chemical scaffolds. We report here the isolation and structure elucidation of eight new deoxyenhygrolides (-) from the marine myxobacterium DSM 14875. The herein described deoxyenhygrolides C-J (-) feature a butenolide core with an ethyl residue at C-3 of the γ-lactone in contrast to the previously described derivatives, deoxyenhygrolides A and B, which feature an isobutyl residue at this position.
View Article and Find Full Text PDFSci Rep
February 2021
Department of BioMolecular Sciences, University of Mississippi, University, MS, USA.
Considered a key taxon in soil and marine microbial communities, myxobacteria exist as coordinated swarms that utilize a combination of lytic enzymes and specialized metabolites to facilitate predation of microbes. This capacity to produce specialized metabolites and the associated abundance of biosynthetic pathways contained within their genomes have motivated continued drug discovery efforts from myxobacteria. Of all myxobacterial biosynthetic gene clusters deposited in the antiSMASH database, only one putative acylhomoserine lactone (AHL) synthase, agpI, was observed, in genome data from Archangium gephyra.
View Article and Find Full Text PDFMar Drugs
December 2019
Pharmaceutical Sciences Division, University of Wisconsin-Madison, Madison, WI 53705, USA.
To date, studies describing myxobacterial secondary metabolites have been relatively scarce in comparison to those addressing actinobacterial secondary metabolites. This realization suggests the immense potential of myxobacteria as an intriguing source of secondary metabolites with unusual structural features and a wide array of biological activities. Marine-derived myxobacteria are especially attractive due to their unique biosynthetic gene clusters, although they are more difficult to handle than terrestrial myxobacteria.
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