Melittin
Major component of bee venom that potently disrupts cell membranes, studied for antimicrobial and anticancer applications.
Chemical Identity
| Property | Value |
|---|---|
| Chemical Formula | C131H229N39O31 |
| Molecular Weight | 2846 Da |
| CAS Number | 20449-79-0 |
| Peptide Class | Bee Venom Peptide (26 amino acids) |
| Sequence | GIGAVLKVLTTGLPALISWIKRKRQQ-NH2 |
| Origin | Apis mellifera (honeybee) |
Structure
Melittin is a 26-amino acid amphipathic peptide comprising 50% of dry honeybee venom weight. It has a hydrophobic N-terminal region (residues 1-20) and a cationic C-terminal region (residues 21-26). In aqueous solution, melittin exists as a random coil but folds into an alpha-helix upon membrane binding, forming tetrameric pores.
Mechanism of Action
Melittin inserts into lipid bilayers, initially lying parallel to the membrane surface (carpet mechanism), then inserting vertically to form toroidal pores. At high concentrations, it causes complete membrane disruption. Unlike many AMPs, melittin is equally potent against gram-positive and gram-negative bacteria, but also hemolytic.
Clinical Applications
- Research tool: Model peptide for membrane biophysics
- Anticancer research: Selective toxicity against cancer cells
- Anti-inflammatory: Phospholipase A2 inhibition
- Drug delivery: Membrane permeabilization for intracellular delivery
- Rheumatology: Bee venom therapy (traditional)
Pharmacology
- Spectrum: Broad (bacteria, cancer cells, red blood cells)
- Hemolysis: Significant (limits therapeutic use)
- Membrane selectivity: Less selective than other AMPs
- Tetramerization: Self-associates in solution and membranes
References
- Habermann, E., & Jentsch, J. (1967). Sequence analysis of melittin. FEBS Letters, 1, 165-167.
- Rady, I., et al. (2017). Melittin, a major peptide component of bee venom, and its conjugates in cancer therapy. Toxicon, 110, 156-167.
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