9SII | pdb_00009sii

Supercoiling bacterial archaellum filament from L. aerophila


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.40 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation   3D Report Full Report


This is version 1.0 of the entry. See complete history


Literature

Structure of a functional archaellum in Bacteria of the Chloroflexota phylum.

Sivabalasarma, S.Taib, N.Mollat, C.L.Joest, M.Steimle, S.Gribaldo, S.Albers, S.V.

(2025) Nat Microbiol 10: 2412-2424

  • DOI: https://doi.org/10.1038/s41564-025-02110-8
  • Primary Citation of Related Structures:  
    9SIE, 9SII

  • PubMed Abstract: 

    Motility in Archaea is driven by the archaellum, a rotary ATP-driven machinery unrelated to the bacterial flagellum. To date, archaella have been described exclusively in archaea; however, recent work reported archaellum genes in bacterial strains of the SAR202 clade (Chloroflexota). Here, using MacSyFinder, we show that bona fide archaellum gene clusters are widespread in several members of the Chloroflexota. Analysis of archaellum-encoding loci and Alphafold3-predicted structures show similarity to the archaellum machinery. Using cryo electron microscopy single-particle analysis, we solved the structure of the bacterial archaellum from Litorilinea aerophila to 2.7 Å. We also show the expression and assembly of this machinery in bacteria and its function in swimming motility. Finally, a phylogenomic analysis revealed two horizontal gene transfer events from euryarchaeal members to Chloroflexota. In summary, our study shows that a functional and assembled archaellum machinery can be exchanged between the two prokaryotic domains.


  • Organizational Affiliation
    • Faculty of Biology, Molecular Biology of Archaea, University of Freiburg, Freiburg, Germany.

Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Flagellin183Litorilinea aerophilaMutation(s): 0 
UniProt
Find proteins for A0A540VDN8 (Litorilinea aerophila)
Explore A0A540VDN8 
Go to UniProtKB:  A0A540VDN8
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A540VDN8
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.40 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.21.2_5419
RECONSTRUCTIONcryoSPARC

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
German Research Foundation (DFG)Germany403222702

Revision History  (Full details and data files)

  • Version 1.0: 2026-01-28
    Type: Initial release