Aβ(1-42) tetramer and octamer structures reveal edge conductivity pores as a mechanism for membrane damage.

Ciudad S, Puig E, Botzanowski T, Meigooni M, Arango AS, Do J, Mayzel M, Bayoumi M, Chaignepain S, Maglia G, Cianferani S, Orekhov V, Tajkhorshid E, Bardiaux B, Carulla N

Nat Commun 11 (1) 3014 [2020-06-15; online 2020-06-15]

Formation of amyloid-beta (Aβ) oligomer pores in the membrane of neurons has been proposed to explain neurotoxicity in Alzheimer's disease (AD). Here, we present the three-dimensional structure of an Aβ oligomer formed in a membrane mimicking environment, namely an Aβ(1-42) tetramer, which comprises a six stranded β-sheet core. The two faces of the β-sheet core are hydrophobic and surrounded by the membrane-mimicking environment while the edges are hydrophilic and solvent-exposed. By increasing the concentration of Aβ(1-42) in the sample, Aβ(1-42) octamers are also formed, made by two Aβ(1-42) tetramers facing each other forming a β-sandwich structure. Notably, Aβ(1-42) tetramers and octamers inserted into lipid bilayers as well-defined pores. To establish oligomer structure-membrane activity relationships, molecular dynamics simulations were carried out. These studies revealed a mechanism of membrane disruption in which water permeation occurred through lipid-stabilized pores mediated by the hydrophilic residues located on the core β-sheets edges of the oligomers.

Swedish NMR Centre (SNC) [Collaborative]

PubMed 32541820

DOI 10.1038/s41467-020-16566-1

Crossref 10.1038/s41467-020-16566-1

pii: 10.1038/s41467-020-16566-1
pmc: PMC7296003