Melectin: a novel antimicrobial peptide from the venom of the cleptoparasitic bee Melecta albifrons

Chembiochem. 2008 Nov 24;9(17):2815-21. doi: 10.1002/cbic.200800476.


A novel antimicrobial peptide designated melectin was isolated from the venom of the cleptoparasitic bee Melecta albifrons. Its primary sequence was established as H-Gly-Phe-Leu-Ser-Ile-Leu-Lys-Lys-Val-Leu-Pro-Lys-Val-Met-Ala-His-Met-Lys-NH(2) by Edman degradation and ESI-QTOF mass spectrometry. Synthetic melectin exhibited antimicrobial activity against both gram-positive and -negative bacteria and it degranulated rat peritoneal mast cells, but its hemolytic activity was low. The CD spectra of melectin measured in the presence of trifluoroethanol and sodium dodecyl sulfate showed a high content alpha-helices, which indicates that melectin can adopt an amphipathic alpha-helical secondary structure in an anisotropic environment such as the bacterial cell membrane. To envisage the role of the proline residue located in the middle of the peptide chain on biological activity and secondary structure, we prepared several melectin analogues in which the Pro11 residue was either replaced by other amino acid residues or was omitted. The results of biological testing suggest that a Pro kink in the alpha-helical structure of melectin plays an important role in selectivity for bacterial cells. In addition, a series of N- and C-terminal-shortened analogues was synthesized to examine which region of the peptide is related to antimicrobial activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology*
  • Antimicrobial Cationic Peptides / chemical synthesis
  • Antimicrobial Cationic Peptides / isolation & purification
  • Antimicrobial Cationic Peptides / pharmacology*
  • Bee Venoms / chemistry*
  • Bees*
  • Cell Degranulation / drug effects
  • Chromatography, High Pressure Liquid
  • Circular Dichroism
  • Erythrocytes / drug effects
  • Gram-Negative Bacteria / drug effects
  • Gram-Positive Bacteria / drug effects
  • Hemolysis / drug effects
  • Hydrophobic and Hydrophilic Interactions
  • Inhibitory Concentration 50
  • Mast Cells / drug effects
  • Mast Cells / physiology
  • Microbial Sensitivity Tests
  • Molecular Sequence Data
  • Protein Structure, Secondary
  • Rats
  • Rats, Wistar
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Anti-Bacterial Agents
  • Antimicrobial Cationic Peptides
  • Bee Venoms
  • melectin