Identification of an amyloidogenic region on keratoepithelin via synthetic peptides

FEBS Lett. 2007 Jan 23;581(2):241-7. doi: 10.1016/j.febslet.2006.12.019. Epub 2006 Dec 18.


Mutations of keratoepithelin (KE) gene in human chromosome 5q31 have been linked with corneal epithelial or stromal dystrophies characterized by the abnormal deposits of amyloid fibrils and/or non-amyloid aggregations in corneal tissue. We report herein that synthetic peptide containing amino acid (a.a.) residues of 515-532 of native KE protein can readily form beta-sheet-containing amyloid fibrils in vitro. Amyloid fibrils formed in various conditions from short synthetic peptides (containing a.a. 515-532 and 515-525, respectively) were characterized by thioflavin T (ThT) fluorescence assay, Congo red staining, electron microscopy (EM) and circular dichroism (CD). Triple-N-methylation of the synthetic peptides prevented the beta-sheet polymerization and related amyloid fibril formation. Comparison study with ThT fluorescence further demonstrated that synthetic peptides containing corneal dystrophy-related mutations within this region formed amyloid fibrils to various extents. Our results suggest that each individual dystrophy-related mutation by itself does not necessarily potentiate amyloid fibril formation of KE. Roles of these intrinsically amyloidogenic foci in abnormal KE aggregations and amyloid deposits of stromal corneal dystrophies await further investigation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amyloid / chemistry*
  • Amyloid / ultrastructure
  • Benzothiazoles
  • Circular Dichroism
  • Congo Red
  • Extracellular Matrix Proteins / chemistry*
  • Extracellular Matrix Proteins / genetics
  • Fluorescence
  • Humans
  • Methylation
  • Molecular Sequence Data
  • Mutation
  • Peptides / chemical synthesis
  • Peptides / chemistry
  • Protein Structure, Secondary
  • Thiazoles / chemistry
  • Transforming Growth Factor beta / chemistry*
  • Transforming Growth Factor beta / genetics


  • Amyloid
  • Benzothiazoles
  • Extracellular Matrix Proteins
  • Peptides
  • Thiazoles
  • Transforming Growth Factor beta
  • betaIG-H3 protein
  • thioflavin T
  • Congo Red