NMR structure of DEF-DAA, a mutant of anopheles defensin DEF-AAA

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: structures with the lowest energy and the least restraint violations 

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Rational design of peptides active against the gram positive bacteria Staphylococcus aureus

Landon, C.Barbault, F.Legrain, M.Guenneugues, M.Vovelle, F.

(2008) Proteins 72: 229-239

  • DOI: https://doi.org/10.1002/prot.21912
  • Primary Citation of Related Structures:  
    2E3E, 2E3F, 2E3G, 2NY8, 2NY9, 2NZ3

  • PubMed Abstract: 

    In an attempt to increase the antimicrobial activity of the insect defensin from Anopheles gambiae, which is active against Staphylococcus aureus at low concentration, hybrid defensins were designed by combining conserved sequence regions and variable regions of insect defensins. Their activity against S. aureus strains sensitive and resistant to conventional antibiotics was evaluated, and the toxicity of the most active molecules was tested. The three-dimensional structure of Anopheles gambiae defensin and five hybrids were determined by NMR and molecular modelling. This strategy led to the design of two chimeric defensins with increased activity compared with the native molecule, but one of them appears to be toxic to mice at a rather low concentration. The structure of the CS alphabeta motif, which is a characteristic of insect defensin, is sensitive to sequence modifications, in particular in the N-terminal loop. The existence of the CS alphabeta is most probably a prerequisite for the stability and the activity of the molecule, but is not sufficient by itself since the hybrid displaying the best defined structure is not active against the tested strains. The analysis of the structure, in relation with the activity and the toxicity data, underlines the importance of turns and of the N-terminal loop. Residues located in the turns contributing to the preservation of positive electrostatic areas at the surface of the molecules seem particularly important for the activity of the molecule, while residues involved in the N-terminal loop are both involved in the modulation of the activity and the toxicity of the molecule.

  • Organizational Affiliation

    Centre de Biophysique Moléculaire, CNRS UPR4301, University of Orleans, rue Charles Sadron, 45071 Orléans, cedex 2, France. landon@cnrs-orleans.fr

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
defensin, mutant DEF-DAA40Anopheles gambiaeMutation(s): 7 
Gene Names: DEF1
Find proteins for Q17027 (Anopheles gambiae)
Explore Q17027 
Go to UniProtKB:  Q17027
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ17027
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 10 
  • Selection Criteria: structures with the lowest energy and the least restraint violations 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-11-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-20
    Changes: Database references, Derived calculations