A1 Refereed original research article in a scientific journal
Antiparallel stacking of Csu pili drives Acinetobacter baumannii 3D biofilm assembly
Authors: Malmi, Henri; Pakharukova, Natalia; Paul, Bindusmita; Tuittila, Minna; Ahmad, Irfan; Knight, Stefan David; Uhlin, Bernt Eric; Ghosal, Debnath; Zavialov, Anton V.
Publisher: Springer Science and Business Media LLC
Publication year: 2026
Journal: Nature Communications
Article number: 2508
Volume: 17
Issue: 1
eISSN: 2041-1723
DOI: https://doi.org/10.1038/s41467-026-68860-z
Publication's open availability at the time of reporting: Open Access
Publication channel's open availability : Open Access publication channel
Web address : https://doi.org/10.1038/s41467-026-68860-z
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/515594977
Self-archived copy's licence: CC BY
Self-archived copy's version: Publisher`s PDF
Many Gram-negative nosocomial pathogens rely on adhesive filaments, known as archaic chaperone-usher pili, to establish stress- and drug-resistant, multi-layered biofilms. Here, we uncover the mechanism by which these pili build three-dimensional (3D) biofilm architectures. In situ analyses of Acinetobacter baumannii biofilms using electron microscopy (EM) reveal an extensive network of ultrathin, flat stacks of archaic Csu pili interconnecting bacterial cells in 3D space. Cryo-EM structures of a single native pilus, pilus pairs, and two types of multi-pilus stacks show that the pili pack into antiparallel sheets, with their rods connected laterally by junctions at their zigzag corners. This antiparallel arrangement ensures that contacts form primarily between pili from interacting cells rather than pili from the same cell. With a remarkably short helical repeat, archaic chaperone-usher pili spontaneously establish a high density of junctions that determines the biofilm’s 3D architecture. Our findings may help develop new therapies against multidrug-resistant bacterial infections by targeting pilus-pilus interactions.
Downloadable publication This is an electronic reprint of the original article. |  |
Funding information in the publication:
This work was supported by grants from the Academy of Finland (321762 and 360760) and S. Juselius Foundation (2023) to A.V.Z.; NHMRC (APP1196924) and The Cumming Global Centre for Pandemic Therapeutics Foundation to D.G.; the Swedish Research Council (SRC) (2019-01720), Kempestiftelserna (SMK21-0076) and The Faculty of Medicine, Umeå University (Insamlingsstiftelsen grant 2021-2023) to B.E.U.; SRC (2020-06136) to I.A.; and an Instrumentarium Science Foundation and a Finnish Cultural Foundation stipends to H.M.
