Contribution of Specific Residues of the β-Solenoid Fold to HET-s Prion Function, Amyloid Structure and Stability

• DOI: 10.1371/journal.ppat.1004158
• Publication Date: 2014-06-12T22:57:09Z
• Authors: Asen Daskalov; Matthias Gantner; Marielle Aulikki ...; Thierry Schmidlin; Celestine N. Chi; Christian Wasmer; Anne Schütz; Johanna Ceschin; Corinne Clavé; Sandra Cescau; Beat Meier; Roland Riek; Sven J. Saupe
• Keywords: Amyloid (mycology); Fungal prion; Podospora anserina

The [Het-s] prion of the fungus Podospora anserina represents a good model system for studying structure-function relationship in amyloid proteins because high resolution solid-state NMR structure form HET-s forming domain (PFD) is available. PFD adopts specific β-solenoid fold with two rungs β-strands delimiting triangular hydrophobic core. A C-terminal loop folds back onto rigid core region and forms more dynamic semi-hydrophobic pocket extending Herein, an alanine scanning mutagenesis was conducted. Different structural elements identified such as core, salt bridges, asparagines ladders were altered effect these mutations on function, fibril stability assayed. Prion activity found to be very robust; only few key able corrupt function. While some strongly destabilize fold, many substitutions fact increase fold. This did not influence formation propensity vivo. However, if Ala replacement alter or shape denaturation curve, corresponding variant showed decreased efficacy. It also finding that addition region, aromatic residues are critical propagation. Mutations latter either positively negatively affected formation. We thus identify modulates although it part cross-β observation might relevant other models.