Margitta Dathe

Publications (2)8.31 Total impact

• Source

  Available from: unibe.ch

  Article: Cupiennin 1d*: the cytolytic activity depends on the hydrophobic N-terminus and is modulated by the polar C-terminus.

  Lucia Kuhn-Nentwig, Margitta Dathe, Alfred Walz, Johann Schaller, Wolfgang Nentwig
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  ABSTRACT: To investigate structural features modulating the biological activity of cupiennin 1 peptides from the spider Cupiennius salei, three truncated cupiennin 1d analogs were synthesized. The fact that their growth inhibiting effect on Gram-negative and Gram-positive bacteria, their lytic activity with human red blood cells and their insecticidal effect on Drosophila melanogaster correlates with structural properties shows that the hydrophobic N-terminal chain segment includes the major determinants of structure and activity. The polar C-terminus seems to modulate peptide accumulation at negatively charged cell surfaces via electrostatic interactions and has no important effect on the peptides' amphipathic secondary structure.
  FEBS Letters 10/2002; 527(1-3):193-8. · 3.54 Impact Factor
• Article: Cupiennin 1, a new family of highly basic antimicrobial peptides in the venom of the spider Cupiennius salei (Ctenidae).

  Lucia Kuhn-Nentwig, Jurg Muller, Johann Schaller, Alfred Walz, Margitta Dathe, Wolfgang Nentwig
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  ABSTRACT: A new family of antimicrobial peptides was isolated from the venom of Cupiennius salei. The peptides were purified to homogeneity, and the sequence of cupiennin 1a was determined by Edman degradation: GFGALFKFLAKKVAKTVAKQAAKQGAKYVVNKQME-NH(2). The amino acid sequences of cupiennin 1b, c, and d were obtained by a combination of sequence analysis and mass spectrometric measurements of comparative tryptic peptide mapping. All peptides consist of 35 amino acid residues and are characterized by a more hydrophobic N-terminal chain region and a C terminus composed preferentially of polar and charged residues. The total charge of all cupiennins calculated under physiological conditions is +8, and their C terminus, formed by a glutamic acid residue, is amidated. Conformational studies of the peptides revealed a high helix forming potential. Antimicrobial assays on bacteria with cupiennin 1a, 1d, and synthesized cupiennins 1a* and 1d* showed minimal inhibitory concentrations for bacteria in the submicromolar range. Their lytic effect on human red blood cells was lower by a factor of 8 to 14 than the highly hemolytic melittin. Cupiennin 1a, 1b, 1d, 1a*, and 1d* showed pronounced insecticidal activity. The immediate biological effects and the structural properties of the isolated cupiennins indicate a membrane-destroying mode of action on prokaryotic as well as eukaryotic cells.
  Journal of Biological Chemistry 04/2002; 277(13):11208-16. · 4.77 Impact Factor