title: A radish seed antifungal peptide with a high amyloid fibril-forming propensity.
abstract: The amyloid fibril-forming ability of two closely related antifungal and antimicrobial peptides derived from plant defensin proteins has been investigated. As assessed by sequence analysis, thioflavin T binding, transmission electron microscopy, atomic force microscopy and X-ray fiber diffraction, a 19 amino acid fragment from the C-terminal region of Raphanus sativus antifungal protein, known as RsAFP-19, is highly amyloidogenic. Further, its fibrillar morphology can be altered by externally controlled conditions. Freezing and thawing led to amyloid fibril formation which was accompanied by loss of RsAFP-19 antifungal activity. A second, closely related antifungal peptide displayed no fibril-forming capacity. It is concluded that while fibril formation is not associated with the antifungal properties of these peptides, the peptide RsAFP-19 is of potential use as a controllable, highly amyloidogenic small peptide for investigating the structure of amyloid fibrils and their mechanism of formation.
authors.affiliation: School of Chemistry and Physics, The University of Adelaide, Adelaide, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Garvey
authors.forename: Sarah
authors.initials: S
authors.lastname: Meehan
authors.forename: Sally L
authors.initials: SL
authors.lastname: Gras
authors.forename: Horst J
authors.initials: HJ
authors.lastname: Schirra
authors.forename: David J
authors.initials: DJ
authors.lastname: Craik
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Van der Weerden
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Anderson
authors.forename: Juliet A
authors.initials: JA
authors.lastname: Gerrard
authors.forename: John A
authors.initials: JA
authors.lastname: Carver
mesh_terms: D000682:Amyloid / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D000935:Antifungal Agents / Q000494:pharmacology*; D052160:Benzothiazoles; D002942:Circular Dichroism; D023082:Defensins / Q000378:metabolism; D005670:Fusarium / Q000187:drug effects* / Q000254:growth & development; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D010446:Peptide Fragments / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D031224:Raphanus / Q000737:chemistry* / Q000378:metabolism; D012639:Seeds / Q000737:chemistry* / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D014026:Nicotiana / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000682:Amyloid; D000935:Antifungal Agents; D052160:Benzothiazoles; D023082:Defensins; D010446:Peptide Fragments; D013844:Thiazoles; C009462:thioflavin T