Orientation of aromatic residues in amyloid cores: Structural insights into prion fiber diversity

Anna Reymer, Kendra K. Frederick, Sra Rocha, Tamás Beke-Somfai, Catherine C. Kitts, Susan Lindquist, Bengt Nordén

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Structural conversion of one given protein sequence into different amyloid states, resulting in distinct phenotypes, is one of the most intriguing phenomena of protein biology. Despite great efforts the structural origin of prion diversity remains elusive, mainly because amyloids are insoluble yet noncrystalline and therefore not easily amenable to traditional structural-biology methods. We investigate two different phenotypic prion strains, weak and strong, of yeast translation termination factor Sup35 with respect to angular orientation of tyrosines using polarized light spectroscopy. By applying a combination of alignment methods the degree of fiber orientation can be assessed, which allows a relatively accurate determination of the aromatic ring angles. Surprisingly, the strains show identical average orientations of the tyrosines, which are evenly spread through the amyloid core. Small variations between the two strains are related to the local environment of a fraction of tyrosines outside the core, potentially reflecting differences in fibril packing.

Original languageEnglish (US)
Pages (from-to)17158-17163
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number48
StatePublished - Dec 2 2014


  • Linear dichroism
  • Polarized light
  • Prion proteins
  • Sup35 strains
  • Tyrosine

ASJC Scopus subject areas

  • General


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