Solution structure of the Moebius cyclotide kalata B2

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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This is version 1.3 of the entry. See complete history


Isolation, Solution Structure, and Insecticidal Activity of Kalata B2, a Circular Protein with a Twist: Do Mobius Strips Exist in Nature?(,)

Jennings, C.V.Rosengren, K.J.Daly, N.L.Plan, M.Stevens, J.Scanlon, M.J.Waine, C.Norman, D.G.Anderson, M.A.Craik, D.J.

(2005) Biochemistry 44: 851-860

  • DOI: https://doi.org/10.1021/bi047837h
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A large number of macrocyclic miniproteins with diverse biological activities have been isolated from the Rubiaceae, Violaceae, and Cucurbitaceae plant families in recent years. Here we report the three-dimensional structure determined using (1)H NMR spectroscopy and demonstrate potent insecticidal activity for one of these peptides, kalata B2. This peptide is one of the major components of an extract from the leaves of the plant Oldenlandia affinis. The structure consists of a distorted triple-stranded beta-sheet and a cystine knot arrangement of the disulfide bonds and is similar to those described for other members of the cyclotide family. The unique cyclic and knotted nature of these molecules makes them a fascinating example of topologically complex proteins. Examination of the sequences reveals that they can be separated into two subfamilies, one of which contains a larger number of positively charged residues and has a bracelet-like circularization of the backbone. The second subfamily contains a backbone twist due to a cis-peptidyl-proline bond and may conceptually be regarded as a molecular Mobius strip. Kalata B2 is the second putative member of the Mobius cyclotide family to be structurally characterized and has a cis-peptidyl-proline bond, thus validating the suggested name for this subfamily of cyclotides. The observation that kalata B2 inhibits the growth and development of Helicoverpa armigera larvae suggests a role for the cyclotides in plant defense. A comparison of the sequences and structures of kalata B1 and B2 provides insight into the biological activity of these peptides.

  • Organizational Affiliation

    Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia 3086.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
kalata B229Oldenlandia affinisMutation(s): 0 
Membrane Entity: Yes 
Find proteins for P58454 (Oldenlandia affinis)
Explore P58454 
Go to UniProtKB:  P58454
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP58454
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • 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: 2004-08-10
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-03-02
    Changes: Data collection, Database references, Derived calculations