Details

Autor(en) / Beteiligte

• Lee, Jiyong
• Culyba, Elizabeth K
• Powers, Evan T
• Kelly, Jeffery W

Titel

Amyloid-β forms fibrils by nucleated conformational conversion of oligomers

Ist Teil von

• Nature chemical biology, 2011-07, Vol.7 (9), p.602-609

Ort / Verlag

United States

Erscheinungsjahr

2011

Quelle

MEDLINE

Beschreibungen/Notizen

• Amyloid-β amyloidogenesis is reported to occur via a nucleated polymerization mechanism. If this is true, the energetically unfavorable oligomeric nucleus should be very hard to detect. However, many laboratories have detected early nonfibrillar amyloid-β oligomers without observing amyloid fibrils, suggesting that a mechanistic revision may be needed. Here we introduce Cys-Cys-amyloid-β(1-40), which cannot bind to the latent fluorophore FlAsH as a monomer, but can bind FlAsH as an nonfibrillar oligomer or as a fibril, rendering the conjugates fluorescent. Through FlAsH monitoring of Cys-Cys-amyloid-β(1-40) aggregation, we found that amyloid-β(1-40) rapidly and efficiently forms spherical oligomers in vitro (85% yield) that are kinetically competent to slowly convert to amyloid fibrils by a nucleated conformational conversion mechanism. This methodology was used to show that plasmalogen ethanolamine vesicles eliminate the proteotoxicity-associated oligomerization phase of amyloid-β amyloidogenesis while allowing fibril formation, rationalizing how low concentrations of plasmalogen ethanolamine in the brain are epidemiologically linked to Alzheimer's disease.