Core–sheath coupling controls flagellar curvature and motility in Leptospira
Year: 2026
Type: article
Abstract: Spirochaete pathogens are among the most invasive bacteria known, causing syphilis, Lyme disease, and leptospirosis. Their tissue penetration depends on periplasmic flagellar filaments that, unlike other bacterial flagella, are encased in a spirochaete-specific multi-protein sheath and deform the cell body into motile waves. How these filaments achieve the mechanical properties needed for invasive motility has remained unclear. Here we determine complete atomic structures of the Leptospira endoflagellar filament, revealing an elaborate sheath of 9 to 12 distinct asymmetrically arranged proteins. We show that the flagellin variant forming the filament core determines sheath composition, producing curvatures ranging from ~3.5 µm −1 to ~5.6 µm −1 . The lower-curvature architecture, employed by pathogenic Leptospira interrogans , proves essential for motility in viscous environments and during infection. Thus, Leptospira achieves environment-specific motility through modular core–sheath coupling, linking atomic-scale structural plasticity to large-scale changes in swimming behaviour. Conservation of key sheath components suggests this mechanism may extend across spirochaetes.
Source: Nature Communications
Authors: Fabiana San Martin, Megan R. Brady, Lenka Fule, Lucienne Nouchikian, Azalia Rodriguez, Magalie Duchateau, Sonia Mondino, Nicole Larrieux, Elsio A. Wunder, Albert I. Ko, Martial Rey, Julia Chamot-Rooke, Rosario Duran, Felipe Trajtenberg, Mathieu Picardeau, Charles V. Sindelar, Alejandro Buschiazzo
Institutions: Institut Pasteur de Montevideo, Yale University, Institut Pasteur, Université Paris Cité, Humboldt-Universität zu Berlin, Centre National de la Recherche Scientifique, AbbVie (Germany), Spectrométrie de Masse pour la Biologie, Instituto de Investigaciones Biológicas Clemente Estable, University of Connecticut, Ministério da Saúde, Fundação Oswaldo Cruz, Université de Montpellier, Institut de Génomique Fonctionnelle
Language: English
Subfield: Parasitology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $6,990
Awards: G1154859969, Development of a Universal Vaccine Against Leptospirosis, Structural basis of motility by dimeric kinesin and myosin motor proteins, Predoctoral Program in Biophysics, Molecular mechanisms of spirochetal motility: the endoflagellum of Leptospira as a working model, Natural History of Urban Leptospirosis, G5255486811, Evolutionary multispecies transcriptomics to reveal genes conferring pathogenicity within Leptospira spp, G8447882725, G8582580391
OpenAlex ID: W7171060216