The solution structure of the circular bacteriocin carnocyclin A (CclA)

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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This is version 1.2 of the entry. See complete history


The three-dimensional structure of carnocyclin A reveals that many circular bacteriocins share a common structural motif.

Martin-Visscher, L.A.Gong, X.Duszyk, M.Vederas, J.C.

(2009) J Biol Chem 284: 28674-28681

  • DOI: https://doi.org/10.1074/jbc.M109.036459
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Carnocyclin A (CclA) is a potent antimicrobial peptide from Carnobacterium maltaromaticum UAL307 that displays a broad spectrum of activity against numerous Gram-positive organisms. An amide bond links the N and C termini of this bacteriocin, imparting stability and structural integrity to this 60-amino acid peptide. CclA interacts with lipid bilayers in a voltage-dependent manner and forms anion selective pores. Several other circular bacteriocins have been reported, yet only one (enterocin AS-48) has been structurally characterized. We have now determined the solution structure of CclA by NMR and further examined its anion binding and membrane channel properties. The results reveal that CclA preferentially binds halide anions and has a structure that is surprisingly similar to that of AS-48 despite low sequence identity, different oligomeric state, and disparate function. CclA folds into a compact globular bundle, comprised of four helices surrounding a hydrophobic core. NMR studies show two fluoride ion binding modes for CclA. Our findings suggest that although other circular bacteriocins are likely to have diverse mechanisms of action, many may have a common structural motif. This shared three-dimensional arrangement resembles the fold of mammalian saposins, peptides that either directly lyse membranes or serve as activators of lipid-degrading enzymes.

  • Organizational Affiliation

    Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Carnocyclin-A60Carnobacterium maltaromaticumMutation(s): 0 
Find proteins for B2MVM5 (Carnobacterium maltaromaticum)
Explore B2MVM5 
Go to UniProtKB:  B2MVM5
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB2MVM5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-08-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2022-03-16
    Changes: Database references, Derived calculations