The Structure of Aβ42 C-Terminal Fragments Probed by a Combined Experimental and Theoretical Study

Chun Wu, Megan M. Murray, Summer L. Bernstein, Margaret M. Condron, Gal Bitan, Joan Emma Shea, Michael T. Bowers

Research output: Contribution to journalArticlepeer-review

74 Scopus citations

Abstract

The C-terminus of amyloid β-protein (Aβ) 42 plays an important role in this protein's oligomerization and may therefore be a good therapeutic target for the treatment of Alzheimer's disease. Certain C-terminal fragments (CTFs) of Aβ42 have been shown to disrupt oligomerization and to strongly inhibit Aβ42-induced neurotoxicity. Here we study the structures of selected CTFs [Aβ(x-42); x = 29-31, 39] using replica exchange molecular dynamics simulations and ion mobility mass spectrometry. Our simulations in explicit solvent reveal that the CTFs adopt a metastable β-structure: β-hairpin for Aβ(x-42) (x = 29-31) and extended β-strand for Aβ(39-42). The β-hairpin of Aβ(30-42) is converted into a turn-coil conformation when the last two hydrophobic residues are removed, suggesting that I41 and A42 are critical in stabilizing the β-hairpin in Aβ42-derived CTFs. The importance of solvent in determining the structure of the CTFs is further highlighted in ion mobility mass spectrometry experiments and solvent-free replica exchange molecular dynamics simulations. A comparison between structures with solvent and structures without solvent reveals that hydrophobic interactions are critical for the formation of β-hairpin. The possible role played by the CTFs in disrupting oligomerization is discussed.

Original languageEnglish (US)
Pages (from-to)492-501
Number of pages10
JournalJournal of molecular biology
Volume387
Issue number2
DOIs
StatePublished - Mar 27 2009
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Structural Biology

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