A radish seed antifungal peptide with a high amyloid fibril-forming propensity

Biochim Biophys Acta. 2013 Aug;1834(8):1615-23. doi: 10.1016/j.bbapap.2013.04.030. Epub 2013 May 9.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid / chemistry*
  • Amyloid / metabolism
  • Amyloid / ultrastructure
  • Antifungal Agents / pharmacology*
  • Benzothiazoles
  • Circular Dichroism
  • Defensins / metabolism
  • Fusarium / drug effects*
  • Fusarium / growth & development
  • Microscopy, Atomic Force
  • Microscopy, Electron, Transmission
  • Peptide Fragments / pharmacology*
  • Protein Structure, Secondary
  • Raphanus / chemistry*
  • Raphanus / metabolism
  • Seeds / chemistry*
  • Seeds / metabolism
  • Thiazoles / metabolism
  • Tobacco / chemistry
  • X-Ray Diffraction

Substances

  • Amyloid
  • Antifungal Agents
  • Benzothiazoles
  • Defensins
  • Peptide Fragments
  • Thiazoles
  • thioflavin T