Secondary Structure Analysis of the Scrapie-Associated Protein PrP 27-30 in Water by Infrared Spectroscopy

Biochemistry. 1991 Aug 6;30(31):7672-80. doi: 10.1021/bi00245a003.

Abstract

A protease-resistant form of the protein PrP (PrP-res) accumulates in tissues of mammals infected with scrapie, Creutzfeldt-Jakob disease, and related transmissible neurodegenerative diseases. This abnormal form of PrP can aggregate into insoluble amyloid-like fibrils and plaques and has been identified as the major component of brain fractions enriched for scrapie infectivity. Using a recently developed technique in Fourier transform infrared spectroscopy which allows protein conformational analysis in aqueous media, we have studied the secondary structure of the proteinase K resistant core of PrP-res (PrP-res 27-30) as it exists in highly infectious fibril preparations. Second-derivative analysis of the infrared spectra has enabled us to quantitate the relative amounts of different secondary structures in the PrP-res aggregates. The analysis indicated that PrP-res 27-30 is predominantly composed of beta-sheet (47%), which is consistent with its amyloid-like properties. In addition, significant amounts of turn (31%) and alpha-helix (17%) were identified, indicating that amyloid-like fibrils need not be exclusively beta-sheet. The infrared-based secondary structure compositions were then used as constraints to improve the theoretical localization of the secondary structures within PrP-res 27-30.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylglucosamine / chemistry
  • Animals
  • Brain / microbiology
  • Cricetinae
  • Electrophoresis, Polyacrylamide Gel
  • Mesocricetus
  • Microscopy, Electron
  • Molecular Weight
  • PrP 27-30 Protein
  • Prions / metabolism*
  • Protein Conformation
  • Scrapie / microbiology
  • Spectrophotometry, Infrared
  • Viral Proteins / biosynthesis
  • Viral Proteins / chemistry*
  • Viral Proteins / isolation & purification
  • Viral Proteins / ultrastructure
  • Water

Substances

  • Prions
  • Viral Proteins
  • Water
  • PrP 27-30 Protein
  • Acetylglucosamine