Crystal structure of the pore-forming toxin FraC from Actinia fragacea (form 2)

Experimental Data Snapshot

  • Resolution: 3.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 

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Pores of the Toxin Frac Assemble Into 2D Hexagonal Clusters in Both Crystal Structures and Model Membranes.

Mechaly, A.E.Bellomio, A.Morante, K.Agirre, J.Gil-Carton, D.Valle, M.Gonzalez-Manas, J.M.Guerin, D.M.A.

(2012) J Struct Biol 180: 312

  • DOI: https://doi.org/10.1016/j.jsb.2012.06.003
  • Primary Citation of Related Structures:  
    3ZWG, 3ZWJ

  • PubMed Abstract: 

    The recent high-resolution structure of the toxin FraC derived from the sea anemone Actinia fragacea has provided new insight into the mechanism of pore formation by actinoporins. In this work, we report two new crystal forms of FraC in its oligomeric prepore conformation. Together with the previously reported structure, these two new structures reveal that ring-like nonamers of the toxin assemble into compact two-dimensional hexagonal arrays. This supramolecular organization is maintained in different relative orientations adopted by the oligomers within the crystal layers. Analyses of the aggregation of FraC pores in both planar and curved (vesicles) model membranes show similar 2D hexagonal arrangements. Our observations support a model in which hexagonal pore-packing is a clustering mechanism that maximizes toxin-driven membrane damage in the target cell.

  • Organizational Affiliation

    Unidad de Biofísica (Centro Mixto CSIC-UPV/EHU), B Sarriena S/N, Campus UPV/EHU Leioa, Leioa, Vizcaya, Spain.

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
179Actinia fragaceaMutation(s): 0 
Find proteins for B9W5G6 (Actinia fragacea)
Explore B9W5G6 
Go to UniProtKB:  B9W5G6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB9W5G6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 3.00 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.204 
  • R-Value Observed: 0.206 
  • Space Group: P 3 1 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 118.77α = 90
b = 118.77β = 90
c = 431.822γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-07-04
    Type: Initial release
  • Version 1.1: 2012-11-07
    Changes: Database references
  • Version 1.2: 2024-05-08
    Changes: Data collection, Database references, Other