Design of a Novel Antimicrobial Peptide Activated by Virulent Proteases

Authors

  • Wataru Aoki,

    1. Research Fellow of the Japan Society for the Promotion of Science, Sakyo-ku, Kyoto 606-8502, Japan
    2. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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  • Nao Kitahara,

    1. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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  • Natsuko Miura,

    1. Research Fellow of the Japan Society for the Promotion of Science, Sakyo-ku, Kyoto 606-8502, Japan
    2. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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  • Hironobu Morisaka,

    1. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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  • Kouichi Kuroda,

    1. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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  • Mitsuyoshi Ueda

    Corresponding author
    1. Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Corresponding author: Mitsuyoshi Ueda, miueda@kais.kyoto-u.ac.jp

Abstract

Antimicrobial peptides are promising antibiotics as they possess strong antimicrobial activity and very broad spectra of activity. However, administration of an antibiotic with a very broad spectrum of activity disrupts normal microflora and increases the risks of other fatal infections. To solve the problem, we designed a novel antimicrobial peptide that is activated by virulent proteases of pathogenic organisms. We constructed a peptide composed of three domains, namely an antimicrobial peptide (lactoferricin) as the active center, a protective peptide (magainin intervening sequence) that suppresses antimicrobial activity, and a specific linker that joins these two components and is efficiently cleaved by virulent proteases. We utilized Candida albicans as a model organism that produces secreted aspartic proteases as a virulence attribute. We screened for a peptide sequence efficiently cleaved by secreted aspartic proteases isozymes and identified a GFIKAFPK peptide as the most favorable substrate. Subsequently, we chemically synthesized a peptide containing the GFIKAFPK sequence. The designed peptide possessed no antimicrobial activity until it was activated by secreted aspartic proteases isozymes. Furthermore, it demonstrated selective antimicrobial activity against C. albicans, but not against Saccharomyces cerevisiae. A designed peptide like the one described in this study may protect normal microflora, resulting in enhanced safety as a therapeutic.

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