Orientation of aromatic residues in amyloid cores: Structural insights into prion fiber diversity
Journal article, 2014
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.
linear dichroism
polarized light
prion proteins
Sup35 strains
tyrosine
Author
Anna Reymer
Chalmers, Chemical and Biological Engineering, Physical Chemistry
K. K. Frederick
Whitehead Institute for Biomedical Research
Howard Hughes Medical Institute
Sandra Rocha
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Tamas Beke-Somfai
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Catherine Kitts
Chalmers, Chemical and Biological Engineering, Physical Chemistry
S. Lindquist
Massachusetts Institute of Technology
Howard Hughes Medical Institute
Whitehead Institute for Biomedical Research
Bengt Nordén
Chalmers, Chemical and Biological Engineering, Physical Chemistry
Proceedings of the National Academy of Sciences of the United States of America
0027-8424 (ISSN) 1091-6490 (eISSN)
Vol. 111 48 17158-17163Subject Categories (SSIF 2011)
Physical Chemistry
DOI
10.1073/pnas.1415663111