A 22-residue engineered magainin that forms toroidal membrane pores against Gram-positive and Gram-negative bacteria.
Also known as: MSI-78 · pexiganan acetate
Part of the Foundational & therapeutic peptides cluster
Overview
Pexiganan (MSI-78) is a 22-amino-acid synthetic antimicrobial peptide derived from the frog-skin peptide magainin 2. It folds into an amphipathic alpha-helix on bacterial membranes and permeabilizes them through toroidal pore formation, and it has been studied as an investigational topical treatment for infected diabetic foot ulcers. This page is educational and not medical advice.
Source & context
Biological / chemical source: Synthetic analog of magainin 2 (frog-skin host-defense peptide)
Primary research or clinical context: Investigational topical agent studied for infected diabetic foot ulcers
Design and mechanism
Pexiganan was engineered from magainin 2 to increase cationic charge and helical amphipathicity. Unstructured in water, it adopts an alpha-helix on contact with anionic bacterial membranes, then inserts near the bilayer surface and induces positive-curvature strain that opens toroidal pores, dissipating membrane potential.
Research history
As a topical 1% cream it advanced through clinical trials for diabetic foot infections but did not gain U.S. regulatory approval. It remains a widely cited reference peptide in studies of membrane-active antimicrobials and structure-activity design.
Sequence
One-letter sequence commonly cited for Pexiganan (educational; isoforms and modifications may differ):
GIGKFLKKAKKFGKAFVKILKK
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
FAQ about Pexiganan
What is Pexiganan?+
Pexiganan (MSI-78) is a 22-amino-acid synthetic antimicrobial peptide derived from the frog-skin peptide magainin 2. It folds into an amphipathic alpha-helix on bacterial membranes and permeabilizes them through toroidal pore formation, and it has been studied as an investigational topical treatment for infected diabetic foot ulcers. This page is educational and not medical advice.
Is Pexiganan an approved medicine?+
Pexiganan is discussed here as a research / educational topic. Investigational topical agent studied for infected diabetic foot ulcers. This is not medical advice.
What is the typical length of Pexiganan?+
Pexiganan is commonly described as approximately 22 amino acids (Synthetic antimicrobial peptide (magainin analog)).