The pyrroloquinoline alkaloid family of natural products, which includes the immunosuppressant lymphostin, has long been postulated to arise from tryptophan. We now report the molecular basis of lymphostin biosynthesis in three marine Salinispora species that maintain conserved biosynthetic gene clusters harboring a hybrid nonribosomal peptide synthetase-polyketide synthase that is central to lymphostin assembly. Through a series of experiments involving gene mutations, stable isotope profiling, and natural product discovery, we report the assembly-line biosynthesis of lymphostin and nine new analogues that exhibit potent mTOR inhibitory activity.
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http://dx.doi.org/10.1021/ja205655w | DOI Listing |
Biochemistry
January 2025
Institute of Microbiology, Eidgenössische Technische Hochschule (ETH) Zurich, Vladimir-Prelog-Weg 4, 8093 Zurich, Switzerland.
Janustatin A is a potently cytotoxic polyketide alkaloid produced at trace amounts by the marine bacterial plant symbiont . Its biosynthetic terminus features an unusual pyridine-containing bicyclic system of unclear origin, in which polyketide and amino acid extension units appear reversed compared to the order of enzymatic modules in the polyketide synthase (PKS)-nonribosomal peptide synthetase (NRPS) assembly line. To elucidate unknown steps in heterocycle formation, we first established robust genome engineering tools in .
View Article and Find Full Text PDFNature
December 2024
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA.
Non-ribosomal peptide synthetases are assembly line biosynthetic pathways that are used to produce critical therapeutic drugs and are typically arranged as large multi-domain proteins called megasynthetases. They synthesize polypeptides using peptidyl carrier proteins that shuttle each amino acid through modular loading, modification and elongation steps, and remain challenging to structurally characterize, owing in part to the inherent dynamics of their multi-domain and multi-modular architectures. Here we have developed site-selective crosslinking probes to conformationally constrain and resolve the interactions between carrier proteins and their partner enzymatic domains.
View Article and Find Full Text PDFACS Chem Biol
December 2024
Department of Structural Biology, University at Buffalo, Buffalo, New York 14203, United States.
Nonribosomal peptide synthetases (NRPSs) produce diverse natural products including siderophores, chelating agents that many pathogenic bacteria produce to survive in low iron conditions. Engineering NRPSs to produce diverse siderophore analogs could lead to the generation of novel antibiotics and imaging agents that take advantage of this unique iron uptake system in bacteria. The highly pathogenic and antibiotic-resistant bacteria produces fimsbactin, an unusual branched siderophore with iron-binding catechol groups bound to a serine or threonine side chain.
View Article and Find Full Text PDFFood Chem
February 2025
State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China. Electronic address:
Elucidating the combined exposure of agrochemicals is essential for safeguarding human health and agroecosystem safety. A rapid and high-sensitivity UHPLC-MS/MS method was developed for simultaneous quantification of nine compounds in sorghum by an assembly-line optimization process with a limit of quantitation of 0.001 mg/kg.
View Article and Find Full Text PDFOrg Lett
November 2024
School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, United States.
The chemical synthesis of -acyl indoles is hindered by the poor nucleophilicity of indolic nitrogen, necessitating the use of strongly basic reaction conditions that encumber elaboration of highly functionalized scaffolds. Herein, we describe the total chemoenzymatic synthesis of the bulbiferamide natural products by the biochemical activity reconstitution of a nonribosomal peptide synthetase assembly line-derived (NRPS-derived) thioesterase that neatly installs the macrocyclizing indolylamide. The enzyme represents a starting point for biocatalytic access to macrocyclic indolylamide peptides and natural products.
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