Abstract
Lipopeptide natural products are essential agents against multidrug-resistant bacteria, but their clinical utility is often constrained by toxicity and resistance. Here, we compare the mechanisms of action of two superficially similar lipopeptide antibiotics: colistin, a last-line treatment for Gram-negative infections, and turnercyclamycins, a new class active against certain colistin-resistant strains. Both antibiotics require lipopolysaccharide (LPS) biosynthesis, even when LPS transport to the outer membrane (OM) is impaired. Colistin rapidly disrupts both the OM and the cytoplasmic membrane (CM), causing swift bacterial death. Turnercyclamycins, by contrast, act independently of the CM, with delayed OM disruption. Unlike colistin, which binds LPS directly to damage membranes, turnercyclamycins show no measurable LPS binding by calorimetry. Instead, their activity is modulated by different phospholipids, as confirmed by phospholipidomic profiling on whole cells, which identifies alterations in bacterial lipid biosynthesis and membrane homeostasis. These findings support a mechanistically distinct mode of action for turnercyclamycins, which we propose to correlate with their different pharmacological properties and potential therapeutic applications. Our results highlight how subtle structural differences between lipopeptides can lead to major functional divergence, offering a framework for the rational design of next-generation antibiotics with improved safety and efficacy profiles.
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Data availability
The DiSC3(5) microscopy data generated in this study have been deposited in FigShare (https://doi.org/10.6084/m9.figshare.30865277). Lipidomics data are available at the NIH Common Fund’s National Metabolomics Data Repository (NMDR)79 website, the Metabolomics Workbench, https://www.metabolomicsworkbench.org where it has been assigned Study ID ST004466. The data can be accessed directly via its Project https://doi.org/10.21228/M84Z8T. This work is supported by NIH grant U2C-DK119886 and OT2-OD030544 grants. All other data are available in the article and its Supplementary files. Source data are provided with this paper.
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Acknowledgements
We thank Colin Manoil and Jeannie Bailey, from the University of Washington, for providing us with wild type and knockout mutants of both Acinetobacter baumannii 5075UW and Acinetobacter baylyi ADP1. We would like to thank Matthew Mulvey, from the University of Utah, for supplying E. coli C600. We would also like to thank Basil Mathew of the University of Utah Department of Pathology for worthwhile discussions. We are grateful for the assistance of John Alan Maschek of University of Utah Metabolomics Core for the lipidomic analysis, Xiang Wang of the University of Utah Cell Imaging Core for the fluorescence microscopy experiments, and to Nancy Chandler and David Belnap of the University of Utah Electron Microscopy Core for the transmission electron microscopy experiments. We would like to thank Amy Barrios of the University of Utah for the use of her plate reader for fluorescence spectroscopy experiments. We would also like to acknowledge the help of Debbie Eckert and Michael Kay for assistance in the isothermal calorimetry experiments. Funding for this project was provided by the National Institute of Allergy and Infectious Disease, National Institutes of Health (NIH R01AI162943). Albebson Lim was also funded by the University of Utah L.S. Skaggs Graduate Student Fellowship provided by the Skaggs Institute for Research.
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A.L.L. and E.W.S. conceptualized and designed the study. A.L.L. and B.W.M. performed experiments and analyzed data. A.L.L., B.W.M., and E.W.S. wrote the manuscript. A.L.L., B.W.M., M.A.F., M.G.H., L.R.B., and E.W.S. reviewed and edited the manuscript. E.W.S. and A.L.L. acquired funding for the project.
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The authors declare the following competing interests: E.W.S., B.W.M., and M.G.H. have submitted a patent application for turnercyclamycins. All other authors declare no competing interests.
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Lim, A.L., Miller, B.W., Fisher, M.A. et al. Differential membrane lipid disruption by lipopeptide antibiotics, colistin and turnercyclamycins. Nat Commun (2026). https://doi.org/10.1038/s41467-026-68681-0
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DOI: https://doi.org/10.1038/s41467-026-68681-0
