Amyloid fibrils prepared using an acetylated and methyl amidated peptide model of the α-Synuclein NAC 71-82 amino acid stretch contain an additional cross-β structure also found in prion proteins

Sci Rep. 2019 Nov 4;9(1):15949. doi: 10.1038/s41598-019-52206-5.

Abstract

The 71-82 fragment of the non-amyloid-β component (NAC) region of the Parkinson's disease (PD) and dementia with Lewy bodies (DLB) related protein α-Synuclein, has been reported to be important during protein misfolding. Although reports have demonstrated the importance of this fragment for the aggregation properties of the full-length protein, its exact role in pre-fibrillar oligomerisation, fibrillar growth and morphology has not yet been fully elucidated. Here, we provide evidence that fibrils prepared from an acetylated and methyl amidated peptide of the NAC 71-82 amino acid stretch of α-Synuclein are amyloid and contain, in addition to the cross-β structure detected in the full-length protein fibrils, a cross-β structure previously observed in prion proteins. These results shed light on the aggregation propensity of the NAC 71-82 amino acid stretch of the full-length protein but also the roles of the N- and C-terminal domains of α-Synuclein in balancing this aggregation propensity. The results also suggest that early aggregated forms of the capped NAC 71-82 peptide generated structures were stabilised by an anti-parallel and twisted β-sheet motif. Due to its expected toxicity, this β-sheet motif may be a promising molecular target for the development of therapeutic strategies for PD and DLB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Amino Acids / chemistry*
  • Amyloid / chemistry*
  • Amyloid / ultrastructure
  • Methylation
  • Molecular Dynamics Simulation
  • Peptides / chemistry*
  • Prion Proteins / chemistry*
  • Protein Conformation
  • Protein Structure, Secondary*
  • Spectroscopy, Fourier Transform Infrared
  • alpha-Synuclein / chemistry*
  • alpha-Synuclein / metabolism

Substances

  • Amino Acids
  • Amyloid
  • Peptides
  • Prion Proteins
  • alpha-Synuclein