Structure of Iho670 Flagellar-like Filament

Experimental Data Snapshot

  • Resolution: 4.00 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

wwPDB Validation   3D Report Full Report

This is version 1.5 of the entry. See complete history


Archaeal flagellin combines a bacterial type IV pilin domain with an Ig-like domain.

Braun, T.Vos, M.R.Kalisman, N.Sherman, N.E.Rachel, R.Wirth, R.Schroder, G.F.Egelman, E.H.

(2016) Proc Natl Acad Sci U S A 113: 10352-10357

  • DOI: https://doi.org/10.1073/pnas.1607756113
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the filament alone, composed of a microtubule-based axoneme, contains more than 400 different proteins. The archaeal flagellar system is simpler still, in some cases having ∼13 different proteins with a single flagellar filament protein. The archaeal flagellar system has no homology to the bacterial one and must have arisen by convergent evolution. However, it has been understood that the N-terminal domain of the archaeal flagellin is a homolog of the N-terminal domain of bacterial type IV pilin, showing once again how proteins can be repurposed in evolution for different functions. Using cryo-EM, we have been able to generate a nearly complete atomic model for a flagellar-like filament of the archaeon Ignicoccus hospitalis from a reconstruction at ∼4-Å resolution. We can now show that the archaeal flagellar filament contains a β-sandwich, previously seen in the FlaF protein that forms the anchor for the archaeal flagellar filament. In contrast to the bacterial flagellar filament, where the outer globular domains make no contact with each other and are not necessary for either assembly or motility, the archaeal flagellin outer domains make extensive contacts with each other that largely determine the interesting mechanical properties of these filaments, allowing these filaments to flex.

  • Organizational Affiliation

    Institute of Complex Systems, Forschungszentrum Jülich, 52425 Juelich, Germany;

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D, E
A, B, C, D, E, F, G, H, I, J, K, L, M, N, O, P, Q, R, S, T, U
303Ignicoccus hospitalisMutation(s): 0 
Gene Names: Igni_0670
Membrane Entity: Yes 
Find proteins for A8AAA0 (Ignicoccus hospitalis (strain KIN4/I / DSM 18386 / JCM 14125))
Explore A8AAA0 
Go to UniProtKB:  A8AAA0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA8AAA0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 4.00 Å
  • Aggregation State: FILAMENT 
  • Reconstruction Method: HELICAL 

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of Biomedical Imaging and Bioengineering (NIH/NIBIB)United StatesEB001567

Revision History  (Full details and data files)

  • Version 1.0: 2016-09-07
    Type: Initial release
  • Version 1.1: 2016-09-14
    Changes: Database references
  • Version 1.2: 2016-09-21
    Changes: Database references
  • Version 1.3: 2016-11-30
    Changes: Refinement description
  • Version 1.4: 2017-09-27
    Changes: Author supporting evidence, Data collection
  • Version 1.5: 2019-12-11
    Changes: Author supporting evidence