Chemical probes that selectively recognize the earliest Aβ oligomers in complex mixtures.

Alzheimer's disease (AD) is characterized by the self-assembly of amyloid beta (Aβ) peptides. Recent models implicate some of the earliest Aβ oligomers, such as trimers and tetramers, in disease. However, the roles of these structures remain uncertain, in part, because selective probes of their formation are not available. Toward that goal, we generated bivalent versions of the known Aβ ligand, the pentapeptide KLVFF. We found that compounds containing sufficiently long linkers (∼19 to 24 Å) recognized primarily Aβ trimers and tetramers, with little binding to either monomer or higher order structures. These compounds might be useful probes for early Aβ oligomers.