title: Solution NMR studies of recombinant Aβ(1-42): from the presence of a micellar entity to residual β-sheet structure in the soluble species.
abstract: Amyloid-β (Aβ) peptide is the major component found in senile plaques of Alzheimer's disease patients. The 42-residue fragment Aβ(1-42) is proposed to be one of the most pathogenic species therein. Here, the soluble Aβ(1-42) species were analyzed by various liquid-state NMR methods. Transient formation of a micelle species was observed at the onset of the aggregation kinetics. This micelle is dissolved after approximately one day. Subsequent loss of this species and the formation of protofibrils are proposed to be the route of fibril formation. Consequently, the observed micelle species is suggested to be on an off-pathway mechanism. Furthermore, characterization of the NMR-observable soluble species shows that it is a random-coil-like entity with low propensities for four β-strands. These β-strands correlate with the β-strand segments observed in Aβ fibrils. This finding indicates that the 3D structure of the fibrils might already be predisposed in the soluble species.
authors: Laboratory of Physical Chemistry, ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich (Switzerland).
authors: Marielle Aulikki
authors: MA
authors: Wälti
authors: Julien
authors: J
authors: Orts
authors: Beat
authors: B
authors: Vögeli
authors: Silvia
authors: S
authors: Campioni
authors: Roland
authors: R
authors: Riek
mesh_terms: D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D006801:Humans; D008823:Micelles; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry*; D066329:Protein Aggregates; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000737:chemistry; D012995:Solubility
chemical_list: D016229:Amyloid beta-Peptides; D008823:Micelles; D010446:Peptide Fragments; D066329:Protein Aggregates; D011994:Recombinant Proteins; C075222:amyloid beta-protein (1-42)
keywords: NMR spectroscopy; amyloid beta-peptides; diffusion ordered spectroscopy; relaxation measurements; saturation transfer difference