Alzheimer's disease is characterized by the oligomerization and amyloid fibril formation of amyloid beta-peptide (Abeta). We describe a novel class of small water-soluble Abeta binding peptidomimetics based on two hydrophobic Ala-Val and Val-Leu dipeptides linked to a D-glucopyranosyl scaffold through aminoalkyl and carboxyethyl links in C1 and C6 positions. These compounds combine the targeting of hydrophobic recognition interfaces with an original hydrophilic sugar beta-breakage strategy. These molecules were shown, by fluorescence thioflavin-T assays, to dramatically slow down the kinetics of amyloid fibril formation even at a low peptidomimetics to Abeta ratio of 0.1:1. Electron microscopy images revealed that the peptidomimetics efficiently reduced the amount of typical amyloid fibrils. NMR saturation transfer difference experiments indicated that these molecules interact with Abeta aggregated species through their hydrophobic amino acid residues. This inhibition effect was found to be sequence-specific since these molecules did not alter the kinetics of aggregation of another amyloid peptide, IAPP, involved in type 2 diabetes mellitus.
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