2. Academic Validation
  3. Helical ultrastructure of the L-ENA spore aggregation factor of a Bacillus paranthracis foodborne outbreak strain

Helical ultrastructure of the L-ENA spore aggregation factor of a Bacillus paranthracis foodborne outbreak strain

  • Nat Commun. 2024 Aug 29;15(1):7514. doi: 10.1038/s41467-024-51804-w.
Mike Sleutel 1 2,  Ephrem Debebe Zegeye 3,  Ann-Katrin Llarena 3,  Brajabandhu Pradhan 4 5,  Marcus Fislage 4 5,  Kristin O'Sullivan 3,  Nani Van Gerven 4 5,  Marina Aspholm 3,  Han Remaut 6 7
Affiliations

Affiliations

  • 1 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium. Mike.Sleutel@vub.be.
  • 2 Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium. Mike.Sleutel@vub.be.
  • 3 Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Ås, Norway.
  • 4 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium.
  • 5 Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium.
  • 6 Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium. Han.Remaut@vub.be.
  • 7 Structural and Molecular Microbiology, Structural Biology Research Center, VIB, Brussels, Belgium. Han.Remaut@vub.be.
PMID: 39209852 DOI: 10.1038/s41467-024-51804-w
Abstract

In pathogenic Bacillota, spores can form an infectious particle and can take up a central role in the environmental persistence and dissemination of disease. A poorly understood aspect of spore-mediated Infection is the fibrous structures or 'endospore appendages' (ENAs) that have been seen to decorate the spores of pathogenic Bacilli and Clostridia. Current methodological approaches are opening a window on these long enigmatic structures. Using cryoID, Alphafold modelling and genetic approaches we identify a sub-class of robust ENAs in a Bacillus paranthracis foodborne outbreak strain. We demonstrate that L-ENA are encoded by a rare three-gene cluster (ena3) that contains all components for the self-assembly of ladder-like protein nanofibers of stacked heptameric rings, their anchoring to the exosporium, and their termination in a trimeric 'ruffle' made of a complement C1Q-like BclA paralogue. The role of ENA fibers in spore-spore interaction and the distribution of L-ENA operon as mobile genetic elements in B. cereus s.l. strains suggest that L-ENA fibers may increase the survival, spread and virulence of these strains.

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