1KD6

Solution structure of the eukaryotic pore-forming cytolysin equinatoxin II


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 250 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with acceptable covalent geometry,structures with the least restraint violations 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Solution structure of the eukaryotic pore-forming cytolysin equinatoxin II: implications for pore formation.

Hinds, M.G.Zhang, W.Anderluh, G.Hansen, P.E.Norton, R.S.

(2002) J.Mol.Biol. 315: 1219-1229

  • DOI: 10.1006/jmbi.2001.5321

  • PubMed Abstract: 
  • Sea anemones produce a family of 18-20 kDa proteins, the actinoporins, that lyse cells by forming pores in cell membranes. Sphingomyelin plays an important role in their lytic activity, with membranes lacking this lipid being largely refractory to th ...

    Sea anemones produce a family of 18-20 kDa proteins, the actinoporins, that lyse cells by forming pores in cell membranes. Sphingomyelin plays an important role in their lytic activity, with membranes lacking this lipid being largely refractory to these toxins. The structure of the actinoporin equinatoxin II in aqueous solution, determined from NMR data, consists of two short helices packed against opposite faces of a beta-sandwich structure formed by two five-stranded beta-sheets. The protein core has extensive hydrophobic interfaces formed by residues projecting from the internal faces of the two beta-sheets. 15N relaxation data show uniform backbone dynamics, implying that equinatoxin II in solution is relatively rigid, except at the N terminus; its inferred rotational correlation time is consistent with values for monomeric proteins of similar mass. Backbone amide exchange rate data also support the view of a stable structure, even though equinatoxin II lacks disulfide bonds. As monitored by NMR, it unfolds at around 70 degrees C at pH 5.5. At 25 degrees C the structure is stable over the pH range 2.5-7.3 but below pH 2.5 it undergoes a slow transition to an incompletely unfolded structure resembling a molten globule. Equinatoxin II has two significant patches of positive electrostatic potential formed by surface-exposed Lys and Arg residues, which may assist its interaction with charged regions of the lipid head groups. Tyr and Trp residues on the surface may also contribute by interacting with the carbonyl groups of the acyl chains of target membranes. Data from mutational studies and truncated analogues identify two regions of the protein involved in membrane interactions, the N-terminal helix and the Trp-rich region. Once the protein is anchored, the N-terminal helix may penetrate the membrane, with up to four helices lining the pore, although other mechanisms of pore formation cannot be ruled out.


    Related Citations: 
    • Sequence-specific resonance assignments of the potent cytolysin equinatoxin II
      Zhang, W.,Hinds, M.G.,Anderluh, G.,Hansen, P.E.,Norton, R.S.
      (2000) J.Biomol.NMR 18: 281


    Organizational Affiliation

    Biomolecular Research Institute, 343 Royal Parade, Parkville 3052, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
EQUINATOXIN II
A
179Actinia equinaMutation(s): 0 
Find proteins for P61914 (Actinia equina)
Go to UniProtKB:  P61914
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 250 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with acceptable covalent geometry,structures with the least restraint violations 
  • Olderado: 1KD6 Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-02-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance