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Jakubec M, Rylandsholm FG, Rainsford P, Silk M, Bril'kov M, Kristoffersen T, Juskewitz E, Ericson JU, Svendsen JSM. Goldilocks Dilemma: LPS Works Both as the Initial Target and a Barrier for the Antimicrobial Action of Cationic AMPs on E. coli. Biomolecules 2023; 13:1155. [PMID: 37509189 PMCID: PMC10377513 DOI: 10.3390/biom13071155] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023] Open
Abstract
Antimicrobial peptides (AMPs) are generally membrane-active compounds that physically disrupt bacterial membranes. Despite extensive research, the precise mode of action of AMPs is still a topic of great debate. This work demonstrates that the initial interaction between the Gram-negative E. coli and AMPs is driven by lipopolysaccharides (LPS) that act as kinetic barriers for the binding of AMPs to the bacterial membrane. A combination of SPR and NMR experiments provide evidence suggesting that cationic AMPs first bind to the negatively charged LPS before reaching a binding place in the lipid bilayer. In the event that the initial LPS-binding is too strong (corresponding to a low dissociation rate), the cationic AMPs cannot effectively get from the LPS to the membrane, and their antimicrobial potency will thus be diminished. On the other hand, the AMPs must also be able to effectively interact with the membrane to exert its activity. The ability of the studied cyclic hexapeptides to bind LPS and to translocate into a lipid membrane is related to the nature of the cationic charge (arginine vs. lysine) and to the distribution of hydrophobicity along the molecule (alternating vs. clumped tryptophan).
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Affiliation(s)
- Martin Jakubec
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Fredrik G Rylandsholm
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Philip Rainsford
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Mitchell Silk
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Maxim Bril'kov
- Department of Pharmacy, Faculty of Health Sciences, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Tone Kristoffersen
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Eric Juskewitz
- Department of Medical Biology, Faculty of Health Sciences, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - Johanna U Ericson
- Department of Medical Biology, Faculty of Health Sciences, UiT the Arctic University of Norway, 9019 Tromsø, Norway
| | - John Sigurd M Svendsen
- Department of Chemistry, Faculty of Science and Technology, UiT the Arctic University of Norway, 9019 Tromsø, Norway
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Langer MK, Rahman A, Dey H, Anderssen T, Blencke HM, Haug T, Stensvåg K, Strøm MB, Bayer A. Investigation of tetrasubstituted heterocycles reveals hydantoins as a promising scaffold for development of novel antimicrobials with membranolytic properties. Eur J Med Chem 2023; 249:115147. [PMID: 36739750 DOI: 10.1016/j.ejmech.2023.115147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/19/2022] [Accepted: 01/21/2023] [Indexed: 01/26/2023]
Abstract
Mimics of antimicrobial peptides (AMPs) have been proposed as a promising class of antimicrobial agents. We report the analysis of five tetrasubstituted, cationic, amphipathic heterocycles as potential AMP mimics. The analysis showed that the heterocyclic scaffold had a strong influence on the haemolytic activity of the compounds, and the hydantoin scaffold was identified as a promising template for drug lead development. Subsequently, a total of 20 hydantoin derivatives were studied for their antimicrobial potency and haemolytic activity. We found 19 of these derivatives to have very low haemolytic toxicity and identified three lead structures, 2dA, 6cG, and 6dG with very promising broad-spectrum antimicrobial activity. Lead structure 6dG displayed minimum inhibitory concentration (MIC) values as low as 1 μg/mL against Gram-positive bacteria and 4-16 μg/mL against Gram-negative bacteria. Initial mode of action (MoA) studies performed on the amine derivative 6cG, utilizing a luciferase-based biosensor assay, suggested a strong membrane disrupting effect on the outer and inner membrane of Escherichia coli. Our findings show that the physical properties and structural arrangement induced by the heterocyclic scaffolds are important factors in the design of AMP mimics.
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Affiliation(s)
- Manuel K Langer
- Department of Chemistry, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Ataur Rahman
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Hymonti Dey
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Trude Anderssen
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Hans-Matti Blencke
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Tor Haug
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Klara Stensvåg
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway
| | - Morten B Strøm
- Department of Pharmacy, Faculty of Health Sciences, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway.
| | - Annette Bayer
- Department of Chemistry, UiT - The Arctic University of Norway, NO-9037, Tromsø, Norway.
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