Mechanistic insights into remodeled Tau-derived PHF6 peptide fibrils by Naphthoquinone-Tryptophan hybrids

Sci Rep. 2018 Jan 8;8(1):71. doi: 10.1038/s41598-017-18443-2.

Abstract

Intra-cellular tau protein tangles and extra-cellular β-amyloid plaques are hallmarks of Alzheimer's disease (AD), characterized by the conversion of natively unfolded monomeric protein/peptide into misfolded β-sheet rich aggregates. Therefore, inhibiting the aggregation cascade or disassembling the pre-formed aggregates becomes a pivotal event in disease treatment. In the present study, we show that Naphthoquinone-Tryptophan hybrids, i.e., NQTrp and Cl-NQTrp significantly disrupted the pre-formed fibrillar aggregates of Tau-derived PHF6 (VQIVYK) peptide and full-length tau protein in vitro, in a dose-dependent manner as evident from ThS assay, CD spectroscopy, and TEM. Molecular dynamics simulation of PHF6 oligomers and fibrils with the Naphthoquinone-Tryptophan hybrids provides a possible structure-function based mechanism-of-action, highlighting the role of hydrophobic interaction and hydrogen bond formation during fibril disassembly. These findings signify the effectiveness of NQTrp and Cl-NQTrp in disassembling fibrillar aggregates and may help in designing novel hybrid molecules for AD treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amino Acid Sequence
  • Amyloid / chemistry*
  • Amyloid / metabolism*
  • Amyloid / ultrastructure
  • Circular Dichroism
  • Humans
  • Models, Molecular
  • Molecular Structure
  • Naphthalenes / chemistry*
  • Peptide Fragments / chemistry*
  • Peptide Fragments / metabolism*
  • Protein Aggregates
  • Protein Aggregation, Pathological
  • Protein Binding
  • Protein Conformation
  • Protein Interaction Domains and Motifs
  • Protein Multimerization
  • Tryptophan / analogs & derivatives*
  • Tryptophan / chemistry*
  • tau Proteins / chemistry*
  • tau Proteins / metabolism*

Substances

  • Amyloid
  • N-(3-chloro-1,4-dihydro-1,4-dioxo-2-naphthalenyl)-L-tryptophan
  • Naphthalenes
  • Peptide Fragments
  • Protein Aggregates
  • tau Proteins
  • Tryptophan