An ATP‐Mediated Antibiotic β‐Peptide Nanofiber That Kills Multidrug‐Resistant Bacteria via a Multistage Mechanism

Artificial bioinspired supramolecular assemblies hold great potential to alter modern medicine. Organic tissue-like nanomaterials built from foldamer peptidomimetics and natural biomolecules could expand our boundaries toward new biocompounds that are able to address global health challenges. Related, antimicrobial resistance against conventional antibiotics motivates search for new compounds with orthogonal mechanisms. Here we designed an antibacterial system where natural adenosine phosphates (APs) trigger supramolecular co-assemblies from a lipopolysaccharide-targeting (LPS) antimicrobial β³-peptide (3K). Cryo-EM and confocal microscopy images on E. coli confirmed that real-time action of 3K-APs progresses via a multiscale mechanism. Initially, entangled nanofibers capture bacteria resulting in agglutination. Further, individual cells become enwrapped, undergoing a reduction in cell height, as observed by AFM. Finally, in situ cryo-EM observations, offering insight into their structural state in solution, suggest an association between the presence of extracellular vesicles and loss of cell integrity, which may contribute to cell death. 3K-ATP was tested on multidrug resistant bacterial strains which adapted to membrane-targeting antibiotics, where only limited cross-resistance was observed. Resistant strains modifying their LPS even showed increased sensitivity. Besides induced disassembly by target membranes, degradation could also be reached through enzymatic hydrolysis of APs, altogether resulting in supramolecular bactericides with controllable build-up and clearance.