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Lookup NU author(s): Dr James ConnollyORCiD
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).
© The Author(s) 2026.Many antibiotics are ineffective against the Gram-negative pathogen Pseudomonas aeruginosa because of intrinsic defence mechanisms, such as the impermeable bacterial outer membrane. Here, we show that protein antibiotics called L-type pyocins kill P. aeruginosa by inhibiting the β-barrel assembly machinery (BAM) complex at the cell surface, halting outer-membrane protein assembly. Using single-particle cryo-electron microscopy, we show that L-type pyocins bind a surface-exposed region of BamA and deploy a C-terminal peptide that competitively inhibits the BAM complex, demonstrating that cell entry is not required for antibiotic activity. We combine genetics, multi-omics and cryo-electron tomography to show that BAM complex inhibition by L-type pyocins or the cyclic-peptide antibiotic, darobactin, triggers a multifaceted transcriptomic, proteomic, and morphological response. BAM inhibition ultimately leads to a catastrophic loss of membrane integrity and cell death. These results validate BAM as a target for antibiotics that do not enter the cell and define an engineerable system for their development.
Author(s): Munder F, Johnson MD, Samuels I, McCaughey L, Zdorevskyi O, Wang C, Kropp A, Zavan L, Price EP, Sarovich DS, Varshney S, McDevitt CA, Venugopal H, Sharma V, Doyle MT, Short F, Ghosal D, Connolly JPR, Knott GJ, Grinter R
Publication type: Article
Publication status: Published
Journal: Nature Communications
Year: 2026
Volume: 17
Issue: 1
Online publication date: 02/07/2026
Acceptance date: 15/06/2026
Date deposited: 25/08/2026
ISSN (electronic): 2041-1723
Publisher: Nature Research
URL: https://doi.org/10.1038/s41467-026-74995-w
DOI: 10.1038/s41467-026-74995-w
Data Access Statement: Cryo-EM maps and atomic models generated in this paper have been deposited in the Protein Data Bank and the Electron Microscopy Data Bank (Accession codes: BAMPAO1=9PXG, EMD-71969; BAMPAO1-Pyocin L1=9PXI, EMD-71970; BAMP28-Pyocin L2=9PXJ, EMD-71971). Existing PDB coordinates used in the study are 5D0O, 7NBX, 4LE7, 4K3B. Raw TraDIS reads are available from the European Nucleotide Archive, study number ERP106484. Raw data from proteomics experiments is available in the PRIDE database, project number PXD067326. Raw data from the BAMPAO1-Pyocin L1 molecular dynamics simulations is available on Zenodo, reference number 18256523. Raw data for RNAseq/transcriptomics experiments is available from the Sequence Read Archive, bioproject number PRJNA1475266. Processed data from TraDIS, proteomics and transcriptomics experiments is provided as supplementary data. [further information at https://www.nature.com/articles/s41467-026-74995-w#data-availability ]
PubMed id: 42393045
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