Targeted modification of a novel amphibian antimicrobial peptide from Phyllomedusa tarsius to enhance its activity against MRSA and microbial biofilm

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    Antimicrobial peptides (AMPs) in the skin secretions of amphibians are fundamental components of a unique defence system that has evolved to protect these hosts from microbial invasion. Medusins constitute a recently-discovered AMP family from phyllomedusine leaf frog skin and exhibit highly-conserved structural characteristics. Here, we report a novel medusin, medusin-PT, from the skin secretion of the Tarsier Leaf Frog, Phyllomedusa tarsius. The mature peptide was initially identified from its cloned biosynthetic precursor-encoding cDNA as obtained by the rapid amplification of cDNA ends (RACE) method. Reverse-phase HPLC and tandem mass spectrometry confirmed both the presence of medusin-PT in the skin secretion and its primary structure. In a range of bioassays, medusin-PT exhibited antimicrobial activity against only the Gram-positive bacterium Staphylococcus aureus at 64 μg/ml. However, after directed changes to enhance the cationicity and amphipathicity of the peptide structure, three analogues showed more potent antimicrobial activity against several additional bacteria including the antibiotic-resistant bacterium MRSA. In addition, these analogues exhibited activity against microbial biofilm (minimum biofilm inhibitory and eradication concentrations of 32 μg/ml and over 64 μg/ml, respectively). These data provide evidence that medusins might be promising candidates as novel antibiotic leads and that the targeted modification of a natural AMP can both improve its efficacy so as to provide new insights into antibiotic design and development.


    Original languageEnglish
    JournalFrontiers in Microbiology
    Journal publication date28 Mar 2017
    Early online date28 Mar 2017
    Publication statusEarly online date - 28 Mar 2017

      Research areas

    • amphibian skin secretion, Molecular cloning, Medusin, Analogue design, MRSA, Antibiofilm

    ID: 127362488