title: Antifungal properties and mode of action of psacotheasin, a novel knottin-type peptide derived from Psacothea hilaris.
abstract: Psacotheasin is a 34-mer knottin-type peptide that is derived from Psacothea hilaris larvae. In this study, the antifungal activity and mechanism(s) by which psacotheasin affects human fungal pathogens were investigated. Psacotheasin shows remarkable antifungal properties without hemolytic activity against human erythrocytes. To understand the antifungal mechanism(s) of psacotheasin in Candida albicans, flow cytometric analysis with DiBAC(4)(3) and PI was conducted. The results showed that psacotheasin depolarized and perturbed the plasma membrane of the C. albicans. Three-dimensional (3D)-flow cytometric contour-plot analysis, accompanied by decreased forward scatter (FS), which indicates cell size, confirmed that psacotheasin exerted antifungal effects via membrane permeabilization. The membrane studies, using a single GUV and FITC-dextran (FD) loaded liposomes, indicate that psacotheasin acts as a pore-forming peptide in the model membrane of C. albicans and the radius of pores were presumed to be anywhere from 2.3 to 3.3nm. Therefore, the current study suggests that the mechanism(s) of psacotheasin's antifungal properties function within the membrane.
authors.affiliation: School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Bomi
authors.initials: B
authors.lastname: Hwang
authors.forename: Jae-Sam
authors.initials: JS
authors.lastname: Hwang
authors.forename: Juneyoung
authors.initials: J
authors.lastname: Lee
authors.forename: Dong Gun
authors.initials: DG
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000302:isolation & purification / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides / Q000302:isolation & purification / Q000494:pharmacology*; D001517:Coleoptera / Q000737:chemistry*; D004912:Erythrocytes / Q000187:drug effects; D005658:Fungi / Q000187:drug effects*; D006461:Hemolysis; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D010455:Peptides; C552739:psacotheasin peptide, Psacothea hilaris