Synthetic peptides

All reagents used for the experiments were high-quality standards from Sigma Aldrich (St. Louis, MO) and Merck (Whitehouse Station, NJ). The synthetic peptides used for immunization and assay development were purchased from American Peptide Company (Sunnyvale, CA).

NTR1 (C47H80O18, molecular weight 933.16, Fig. 1A), with a purity > 99.0%, was purchased from the Chinese National Institutes for Food and Drug Control (Being, China). NTR1 was dissolved in sterile H₂O to make 1 mM stock solution and stored at −20°C.
Human Aβ1-42 oligomers were prepared from commercially available synthetic peptides (American Peptide Company, Inc., Sunnyvale, CA) as described56 (link). Briefly, the lyophilized peptide (1 mg) was resuspended in 250 µL cold 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP, Sigma) and aliquoted in 3 polypropylene vials. After 2 hours of incubation under the hood, HFIP was removed under gentle vacuum to form a thin film of peptide. Sealed vials were then stored at –20°C. Prior to use, 14.8 µL anhydrous DMSO (Sigma) was added to one sealed vial to obtain a pure monomeric Aβ/DMSO solution that was sonicated for 10 min and then aliquoted by 1.6 µL per vial (5 mM). Oligomeric Aβ42 was obtained by incubating an aliquot of monomeric Aβ/DMSO solution in 100 µL sterile PBS or ACSF (80 µM) at 4°C for 24 hours.