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Mag(i+4)1,15

Double-Stapled Antimicrobial Peptide

Mag(i+4)1,15 is a double hydrocarbon-stapled variant of the antimicrobial peptide Magainin-2. Double stapling stabilizes the amphipathic α-helix, conferring enhanced proteolytic resistance and antimicrobial activity compared to the linear peptide.

Disease Target 

Mag(i+4)1,15 targets multidrug-resistant (MDR) bacterial infections, including Staphylococcus and Pseudomonas species, and its double-stapled design provides maximal protease resistance with low red blood cell (RBC) toxicity while maintaining activity against both Gram-positive and Gram-negative bacteria.

Stapling Strategy 

Mag(i+4)1,15 is synthesized using Fmoc-(S)-2-(4-pentenyl)alanine (Fmoc-(S5)-OH, CAS: 288617-73-2) and it enables the solid-phase peptide synthesis (SPPS). During assembly, Fmoc-(S5)-OH is incorporated at two i,i+4 positions (1–5 and 15–19), followed by ruthenium-catalyzed ring-closing olefin metathesis to generate two (CH₂)₄ hydrocarbon staples. The dual stapling locks the peptide into a stabilized α-helical conformation, enhancing cell permeability and antimicrobial activity against both Gram-positive and Gram-negative bacteria, while maintaining low cytotoxicity.

 

Technical specification

KD20 peptide Sequency : Ac-G(S5)GKF(S5)HSKKKFGKA(S5)VGE(S5)AKK-NH₂ (dbl staple)
KD20 peptide MW : 2602.17 g/mol
KD20 peptide Purity : > 95%
KD20 peptide Counter-Ion : TFA Salts
Peptide library synthesis KD20 peptide Delivery format : Lyophilized

Price

 

Product Size Price €
 Price $
SB328-1mg 1 mg 883 1060
SB328-5mg 5 mg 1107 1329
SB328-10mg 10 mg 1612 1934

For more information about stapled peptides, please visit our dedicated page.

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If your target is not listed, we offer custom stapled peptide design and synthesis. Whether you require sequence optimization, specific modifications, or larger production quantities, our team can support your project. Submit your project details and we will provide a personalized proposal.

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2019 Oct;37(10):1186-1197. doi: 10.1038/s41587-019-0222-z. Epub 2019 Aug 19.

Design of stapled antimicrobial peptides that are stable, nontoxic and kill antibiotic-resistant bacteria in mice

Abstract

The clinical translation of cationic α-helical antimicrobial peptides (AMPs) has been hindered by structural instability, proteolytic degradation and in vivo toxicity from nonspecific membrane lysis. Although analyses of hydrophobic content and charge distribution have informed the design of synthetic AMPs with increased potency and reduced in vitro hemolysis, nonspecific membrane toxicity in vivo continues to impede AMP drug development. Here, we analyzed a 58-member library of stapled AMPs (StAMPs) based on magainin II and applied the insights from structure-function-toxicity measurements to devise an algorithm for the design of stable, protease-resistant, potent and nontoxic StAMP prototypes. We show that a lead double-stapled StAMP named Mag(i+4)1,15(A9K,B21A,N22K,S23K) can kill multidrug-resistant Gram-negative pathogens, such as colistin-resistant Acinetobacter baumannii in a mouse peritonitis-sepsis model, without observed hemolysis or renal injury in murine toxicity studies. Inputting the amino acid sequences alone, we further generated membrane-selective StAMPs of pleurocidin, CAP18 and esculentin, highlighting the generalizability of our design platform.

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