title: Solvent Removal Induces a Reversible β-to-α Switch in Oligomeric Aβ Peptide.
abstract: Solvation and hydration are key factors for determining the stability and folding of proteins, as well as the formation of amyloid fibrils and related polypeptide aggregates. Using attenuated total reflectance Fourier-transform infrared and solid-state NMR spectroscopy, we find that the Aβ peptide experiences a remarkable conformational switch from β to α secondary structure upon solvent removal by lyophilization of oligomers. This transition is, contrary to Aβ fibrils, independent of concentration of organic co-solvents or co-solutes and is reversible upon re-addition of the solvent. Our data illuminate a previously unnoted secondary structural plasticity of the Aβ peptide in amyloid oligomers that could bear relevance for Aβ's interactions with cellular structures of low polarity.
authors.affiliation: Institute for Pharmaceutical Biotechnology, Ulm University, Helmholtzstraße 8/1, 89081 Ulm, Germany.
authors.forename: Senthil T
authors.initials: ST
authors.lastname: Kumar
authors.affiliation: Research Group Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research- Fritz Lipmann Institute, Beutenbergstraße 11, 07745 Jena, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Leppert
authors.affiliation: Research Group Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research- Fritz Lipmann Institute, Beutenbergstraße 11, 07745 Jena, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bellstedt
authors.affiliation: Research Group Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research- Fritz Lipmann Institute, Beutenbergstraße 11, 07745 Jena, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wiedemann
authors.affiliation: Institute for Pharmaceutical Biotechnology, Ulm University, Helmholtzstraße 8/1, 89081 Ulm, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Fändrich
authors.affiliation: Research Group Biomolecular NMR Spectroscopy, Leibniz Institute for Age Research- Fritz Lipmann Institute, Beutenbergstraße 11, 07745 Jena, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Görlach
mesh_terms: D016229:Amyloid beta-Peptides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011487:Protein Conformation; D012997:Solvents
chemical_list: D016229:Amyloid beta-Peptides; D012997:Solvents
keywords: amyloid beta peptide; lyophilization; neurodegeneration; protein folding; solid-state NMR spectroscopy