title: Design of a novel antimicrobial peptide activated by virulent proteases.
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.
authors.affiliation: Research Fellow of the Japan Society for the Promotion of Science, Sakyo-ku, Kyoto 606-8502, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Aoki
authors.forename: Nao
authors.initials: N
authors.lastname: Kitahara
authors.forename: Natsuko
authors.initials: N
authors.lastname: Miura
authors.forename: Hironobu
authors.initials: H
authors.lastname: Morisaka
authors.forename: Kouichi
authors.initials: K
authors.lastname: Kuroda
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Ueda
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D057055:Aspartic Acid Proteases / Q000378:metabolism; D002176:Candida albicans / Q000187:drug effects* / Q000201:enzymology*; D002177:Candidiasis / Q000188:drug therapy / Q000382:microbiology; D015195:Drug Design; D006801:Humans; D007781:Lactoferrin / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; C082171:lactoferricin B; D057055:Aspartic Acid Proteases; D010447:Peptide Hydrolases; D007781:Lactoferrin