Formation of oAβ-lipoprotein Complexes

L-α-phosphatidylserine (PS) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were purchased from Avanti Polar Lipids as powder. PS and DMPC were dissolved in chloroform at 10 mg/mL and mixed at 1:4. Chloroform was evaporated under vacuum and formed a thin layer containing the mixture of PS and DMPC. DPBS was added to re-hydrate the lipid mixture to 5 mg/mL, and the liposomes were formed by sonication on ice until the solution becomes translucent. To prepare oAβ-lipoprotein complexes, PS/DMPC liposomes and APOE3 were mixed at final concentrations of 1 mg/mL for PS/DMPC liposomes and 0.25 mg/mL for APOE3. The mixture was incubated at 18 °C 15 min and 30 °C 15 min for 3 cycles [28 (link)]. Then FAM-labeled oAβ was added into the lapidated APOE at a final concentration of 1 μM and incubated at room temperature for 1 hr.