title: Antifungal effect of CopA3 monomer peptide via membrane-active mechanism and stability to proteolysis of enantiomeric D-CopA3.
abstract: In our previous study, coprisin, a 43-mer defensin-like peptide, was derived from the dung beetle, Copris tripartitus, and a 9-mer CopA3 (monomer), truncated coprisin analog peptide, was designed. However, the antifungal effects of CopA3 are not known yet. In this study, the antifungal activity and mechanism of CopA3 were investigated and to develop a more effective antimicrobial peptide under physiological conditions, the enantiomeric d-CopA3 was designed. l- and d-CopA3 had a similar antifungal activity without chiral selectivity, and their activity was more potent than that of melittin used as a positive control. Furthermore, l- and d-CopA3 did not even show any hemolysis against human erythrocytes. Membrane studies using propidium iodide and bis-(1,3-dibutylbarbituric acid) trimethine oxonol [DiBAC4(3)], suggested that the antifungal effect of l- and d-CopA3 was due to the membrane-active mechanism, by contrast with coprisin possessing apoptotic mechanism without membrane permeabilization. Finally, the proteolytic resistance and antifungal activity of l- and d-CopA3 against trypsin was analyzed by HPLC and colony count assay. The results showed that only d-CopA3 maintained a potent antifungal activity despite the proteolytic condition. Therefore, this study suggests that d-CopA3 has potential as a novel antimicrobial agent.
authors.affiliation: School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daehak-ro 80, Buk-gu, Daegu 702-701, South Korea.
authors.forename: Hyemin
authors.initials: H
authors.lastname: Choi
authors.forename: Jae-Sam
authors.initials: JS
authors.lastname: Hwang
authors.forename: Ho
authors.initials: H
authors.lastname: Kim
authors.forename: Dong Gun
authors.initials: DG
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000935:Antifungal Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects; D005658:Fungi / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D019476:Insect Proteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009181:Mycoses / Q000188:drug therapy; D059748:Proteolysis; D013237:Stereoisomerism; D014357:Trypsin / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; C583724:CopA3 peptide, Copris tripartitus; D019476:Insect Proteins; D014357:Trypsin
keywords: 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide; ATCC; American Type Culture Collection; Antimicrobial peptide; CFUs; CH(3)CN; CLSI; Clinical and Laboratory Standards Institute; CopA3; Coprisin; DiBAC(4)(3); Enantiomeric peptide; KCTC; Korean Collection for Type Cultures; MTT; Membrane-active mechanism; PBS; SD; acetonitrile; bis-(1,3-dibutylbarbituric acid) trimethine oxonol; colony-forming units; phosphate buffered saline; standard deviation