Point mutations affecting yeast prion propagation change the structure of its amyloid fibrils

• Published in: Journal of molecular liquids Vol. 314; p. 113618
• Main Authors: Sulatskaya, Anna I., Bondarev, Stanislav A., Sulatsky, Maksim I., Trubitsina, Nina P., Belousov, Mikhail V., Zhouravleva, Galina A., Llanos, Manuel A., Kajava, Andrey V., Kuznetsova, Irina M., Turoverov, Konstantin K.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-09-2020; Elsevier
• Subjects: [PSI+] prion; Amyloid fibril; Beta-serpentine; Binding stoichiometry; Biochemistry, Molecular Biology; Equilibrium microdialysis; Life Sciences; Point mutation; Structural polymorphism; Sup35p; Super-pleated beta-structure; Thioflavin T; Super-pleated beta-structure; [PSI+] prion; Structural polymorphism; Thioflavin T; Sup35p; Equilibrium microdialysis; Point mutation; Binding stoichiometry; Amyloid fibril; Beta-serpentine; super-pleated beta-structure; structural polymorphism; equilibrium microdialysis; binding stoichiometry; amyloid fibril; thioflavin T; point mutation; betaserpentine
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2020.113618

We investigated the effect of the point substitutions in the N-terminal domain of the yeast prion protein Sup35 (Sup35NMp) on the structure of its amyloid fibrils. As the objects of the study, proteins with mutations that have different influence on the [PSI+] prion propagation, but do not prevent the aggregation of Sup35NMp in vitro were chosen. The use of the wide range of physico-chemical methods allowed us to show significant differences in the structure of these aggregates, their physical size, clumping tendency. Also we demonstrated that the fluorescent probe thioflavin T (ThT) can be successfully used for investigation of subtle changes in the structural organization of fibrils formed from various Sup35NMp. The obtained results and our theoretical predictions allowed us to conclude that some of selected amino acid substitutions delimit the region of the protein that forms the core of amyloid fibrils, and change the fibrils structure. The relationship of structural features of in vitro Sup35NMp amyloid aggregates with the stability of the [PSI+] prion in vivo allowed us to suggest that oligopeptide repeats (R) of the amyloidogenic N-terminal domain of Sup35NMp from R0 to R2 play a key role in protein aggregation. Their arrangement rather than just presence is critical for propagation of the strong [PSI+] prion variants. The results confirm the suitability of the proposed combination of theoretical and empirical approaches for identifying changes in the amyloid fibrils structure, which, in turn, can significantly affect both the functional stability of amyloid fibrils and their pathogenicity.
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•Amino acid substitutions in Sup35p oligopeptide repeats change structure of amyloid aggregates.•The fluorescent probe ThT can be used for the investigation of subtle changes in the structural organization of amyloid.•The arrangement of the first two oligopeptide repeats of Sup35p is crucial for the propagation of strong [PSI+] variants.