Spectroscopic Signature for Stable β-Amyloid Fibrils versus β-Sheet-Rich Oligomers.

ABSTRACT: We use two-dimensional IR (2D IR) spectroscopy to explore fibril formation for the two predominant isoforms of the β-amyloid (Aβ_1-40 and Aβ_1-42) protein associated with Alzheimer's disease. Two-dimensional IR spectra resolve a transition at 1610 cm^-1 in Aβ fibrils that does not appear in other Aβ aggregates, even those with predominantly β-sheet-structure-like oligomers. This transition is not resolved in linear IR spectroscopy because it lies under the broad band centered at 1625 cm^-1, which is the traditional infrared signature for amyloid fibrils. The feature is prominent in 2D IR spectra because 2D lineshapes are narrower and scale nonlinearly with transition dipole strengths. Transmission electron microscopy measurements demonstrate that the

SUBMITTER: Lomont JP 

PROVIDER: S-EPMC5969533 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature