Biosynthesis, Mechanism of Action, and Inhibition of the Enterotoxin Tilimycin Produced by the Opportunistic Pathogen Klebsiella oxytoca
| Autor: | Andrew M. Gulick, Courtney C. Aldrich, Eric J. Drake, Valeria Guidolin, Evan M. Alexander, Dale F. Kreitler, Alexander K. Hurben, Silvia Balbo, Peter W. Villalta |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Bacterial Toxins 030106 microbiology Pyrrolobenzodiazepine Enterotoxin behavioral disciplines and activities Article Microbiology Benzodiazepines Enterotoxins 03 medical and health sciences chemistry.chemical_compound Biosynthesis parasitic diseases medicine Pyrroles Microbiome Adenylylation Natural product biology Chemistry Klebsiella oxytoca biology.organism_classification Kinetics 030104 developmental biology Infectious Diseases Mechanism of action medicine.symptom |
| Zdroj: | ACS Infect Dis |
| ISSN: | 2373-8227 |
| Popis: | Tilimycin is an enterotoxin produced by the opportunistic pathogen Klebsiella oxytoca that causes antibiotic-associated hemorrhagic colitis (AAHC). This pyrrolobenzodiazepine (PBD) natural product is synthesized by a bimodular nonribosomal peptide synthetase (NRPS) pathway comprised of three proteins: NpsA, ThdA and NpsB. We describe the functional and structural characterization of the fully reconstituted NRPS system and report the steady-state kinetic analysis of all natural substrates and cofactors as well as the structural characterization of both NpsA and ThdA. The mechanism of action of tilimycin was confirmed using DNA adductomics techniques through the detection of putative N-2 guanine alkylation after tilimycin exposure to eukaryotic cells, providing the first structural characterization of a PBD-DNA adduct formed in cells. Finally, we report the rational design of small-molecule inhibitors that block tilimycin biosynthesis in whole cell K. oxytoca (IC(50) = 29 ± 4 μM) through the inhibition of NpsA (K(D) = 29 ± 4 nM). |
| Databáze: | OpenAIRE |
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