IQ-motif peptides as novel anti-microbial agents

Denise T.F. McLean, Fionnuala T. Lundy, David J. Timson

    Research output: Contribution to journalArticlepeer-review


    The IQ-motif is an amphipathic, often positively charged, α-helical, calmodulin binding sequence found in a number of eukaryote signalling, transport and cytoskeletal proteins. They share common biophysical characteristics with established, cationic α-helical antimicrobial peptides, such as the human cathelicidin LL-37. Therefore, we tested eight peptides encoding the sequences of IQ-motifs derived from the human cytoskeletal scaffolding proteins IQGAP2 and IQGAP3. Some of these peptides were able to inhibit the growth of Escherichia coli and Staphylococcus aureus with minimal inhibitory concentrations (MIC) comparable to LL-37. In addition some IQ-motifs had activity against the fungus Candida albicans. This antimicrobial activity is combined with low haemolytic activity (comparable to, or lower than, that of LL-37). Those IQ-motifs with anti-microbial activity tended to be able to bind to lipopolysaccharide. Some of these were also able to permeabilise the cell membranes of both Gram positive and Gram negative bacteria. These results demonstrate that IQ-motifs are viable lead sequences for the identification and optimisation of novel anti-microbial peptides. Thus, further investigation of the anti-microbial properties of this diverse group of sequences is merited.

    Original languageEnglish
    Pages (from-to)875-880
    Number of pages6
    Issue number4
    Publication statusPublished - 1 Apr 2013


    • α-Helical peptide
    • Anti-microbial peptides
    • Lipopolysaccharide (LPS)
    • LL-37
    • Membrane permeabilisation


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