Aβ(39-42) modulates Aβ oligomerization but not fibril formation

Megan Murray Gessel, Chun Wu, Huiyuan Li, Gal Bitan, Joan Emma Shea, Michael T. Bowers

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Recently, certain C-terminal fragments (CTFs) of Aβ42 have been shown to be effective inhibitors of Aβ42 toxicity. Here, we examine the interactions between the shortest CTF in the original series, Aβ(39-42), and full-length Aβ. Mass spectrometry results indicate that Aβ(39-42) binds directly to Aβ monomers and to the n = 2, 4, and 6 oligomers. The Aβ42:Aβ(39-42) complex is further probed using molecular dynamics simulations. Although the CTF was expected to bind to the hydrophobic C-terminus of Aβ42, the simulations show that Aβ(39-42) binds at several locations on Aβ42, including the C-terminus, other hydrophobic regions, and preferentially in the N-terminus. Ion mobility-mass spectrometry (IM-MS) and electron microscopy experiments indicate that Aβ(39-42) disrupts the early assembly of full-length Aβ. Specifically, the ion-mobility results show that Aβ(39-42) prevents the formation of large decamer/dodecamer Aβ42 species and, moreover, can remove these structures from solution. At the same time, thioflavin T fluorescence and electron microscopy results show that the CTF does not inhibit fibril formation, lending strong support to the hypothesis that oligomers and not amyloid fibrils are the Aβ form responsible for toxicity. The results emphasize the role of small, soluble assemblies in Aβ-induced toxicity and suggest that Aβ(39-42) inhibits Aβ-induced toxicity by a unique mechanism, modulating early assembly into nontoxic hetero-oligomers, without preventing fibril formation.

Original languageEnglish (US)
Pages (from-to)108-117
Number of pages10
JournalBiochemistry
Volume51
Issue number1
DOIs
StatePublished - Jan 10 2012

All Science Journal Classification (ASJC) codes

  • Biochemistry

Fingerprint Dive into the research topics of 'Aβ(39-42) modulates Aβ oligomerization but not fibril formation'. Together they form a unique fingerprint.

Cite this