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Publication Abstract from PubMed

Adhesive pili assembled via the chaperone-usher pathway (CUP) are hair-like appendages that mediate host tissue colonization and biofilm formation of Gram-negative bacteria (1-3). Archaic CUP pili, the most diverse and widespread CUP adhesins, are promising vaccine and drug targets due to their prevalence in the most troublesome multidrug-resistant (MDR) pathogens (1,4,5). However, their architecture and assembly-secretion process remain unknown. Here, we present the 3.4 A resolution cryo-electron microscopy structure of the prototypical archaic Csu pilus that mediates biofilm formation of Acinetobacter baumannii, a notorious MDR nosocomial pathogen. In contrast to the thick helical tubes of the classical type 1 and P pili, archaic pili assemble into a conceptually novel ultrathin zigzag architecture secured by an elegant clinch mechanism. The molecular clinch provides the pilus with high mechanical stability as well as superelasticity, a property observed now for the first time in biomolecules, while enabling a more economical and faster pilus production. Furthermore, we demonstrate that clinch formation at the cell surface drives pilus secretion through the outer membrane. These findings suggest that clinch-formation inhibitors might represent a new strategy to fight MDR bacterial infections.

Archaic chaperone-usher pili self-secrete into superelastic zigzag springs.,Pakharukova N, Malmi H, Tuittila M, Dahlberg T, Ghosal D, Chang YW, Myint SL, Paavilainen S, Knight SD, Lamminmaki U, Uhlin BE, Andersson M, Jensen G, Zavialov AV Nature. 2022 Jul 19. pii: 10.1038/s41586-022-05095-0. doi:, 10.1038/s41586-022-05095-0. PMID:35853476^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.