Magainin 2
Amphibian antimicrobial peptide from Xenopus laevis skin that pioneered the field of host defense peptides.
Chemical Identity
| Property | Value |
|---|---|
| Chemical Formula | C122H210N32O22 |
| Molecular Weight | 2467 Da |
| CAS Number | 106362-32-5 |
| Peptide Class | Amphibian Antimicrobial Peptide |
| Sequence | GIGKFLHSAKKFGKAFVGEIMNS |
| Origin | Xenopus laevis (African clawed frog) |
Structure
Magainin 2 is a 23-amino acid linear amphipathic alpha-helical peptide isolated from the skin of the African clawed frog Xenopus laevis. It was the first antimicrobial peptide discovered in vertebrates, opening an entire field of research. The peptide forms an alpha-helix in membrane environments with distinct hydrophilic and hydrophobic faces.
Mechanism of Action
Magainin 2 disrupts bacterial membranes through its amphipathic alpha-helical structure. The cationic residues interact with anionic phospholipids while the hydrophobic face inserts into the lipid bilayer, forming toroidal pores that cause membrane depolarization and cell lysis. It shows selectivity for bacterial over mammalian membranes.
Clinical Applications
- Pioneer AMP: Foundation for antimicrobial peptide drug development
- Pexiganan: Synthetic analog developed for clinical use
- Cancer research: Selective cytotoxicity against tumor cells
- Agricultural applications: Crop protection agents
Pharmacology
- Spectrum: Broad (gram-positive, gram-negative, fungi)
- Hemolysis: Minimal at antimicrobial concentrations
- Salt sensitivity: Reduced activity in high salt
- Selectivity: Bacterial > mammalian membrane selectivity
References
- Zasloff, M. (1987). Magainins: a class of antimicrobial peptides from Xenopus skin. Proceedings of the National Academy of Sciences, 84, 5449-5453.
- Matsuzaki, K. (1999). Why and how are peptide-lipid interactions utilized for self-defense? Biochimica et Biophysica Acta, 1462, 1-10.
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