Core–sheath coupling controls flagellar curvature and motility in Leptospira

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.

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Publication Details

Journal
Nature Communications
Published
2026-07-25
DOI
https://doi.org/10.1038/s41467-026-75995-6
Primary Topic
Leptospirosis research and findings
Type
article
Field-Weighted Citation Impact
0.00

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article

Core–sheath coupling controls flagellar curvature and motility in Leptospira

Lucienne Nouchikian, Elsio A. Wunder, Fabiana San Martin, Albert Icksang Ko et al.
Nature Communications
Leptospirosis research and findings
article

Core–sheath coupling controls flagellar curvature and motility in Leptospira

Lucienne Nouchikian, Elsio A. Wunder, Fabiana San Martin, Albert Icksang Ko, Martial Rey, N. Larrieux, Megan R. Brady, Felipe Trajtenberg, Rosario Durán, Magalie Duchateau, Julia Chamot‐Rooke, Lenka Fule, Azalia Rodríguez, Alejandro Buschiazzo, Mathieu Picardeau, Charles V. Sindelar, Sonia Mondino
article en

Abstract

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.

Nature Communications
Centre National de la Recherche Scientifique (FR), Institut Pasteur (FR), Université Paris Cité (FR), Yale University (US), Ministério da Saúde (BR), Institut Pasteur de Montevideo (UY), Instituto de Investigaciones Biológicas Clemente Estable (UY), Fundação Oswaldo Cruz (BR), Universidad de Montevideo (UY)
Agencia Nacional de Investigación e Innovación, Agence Nationale de la Recherche, Institut Pasteur, National Institute of General Medical Sciences, National Institute of Allergy and Infectious Diseases
Life below water
Openalex Percentile: Top 7%
Leptospirosis research and findings
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