Metal loading capacity of aβ N-terminus: A combined potentiometrie and spectroscopic study of zinc(II) complexes with Aβ(1-16), its short or mutated peptide fragments and its polyethylene glycol-ylated analogue

Chiara A. Damante, Katalin Ösz, Zoltán Nagy, Giuseppe Pappalardo, Giulia Grasso, Giuseppe Impellizzeri, Enrico Rizzarelli, Imre Sóvágó

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Abstract

Aggregation of the amyloid β-peptide (Aβ) into insoluble fibrils is a key pathological event In Alzheimer's Disease (AD). There is now compelling evidence that metal binding to Aβ Is Involved In AD pathogenesis. The amino acid region 1-16 is widely considered as the metal binding domain of Aβ. In this work, we used a combined Potentiometrie, NMR, and electrospray ionization mass spectrometry (ESI-MS) approach to study the zinc(II) binding to a new polyethylene glycol (PEG)-conjugated peptide fragment encompassing the 1-16 amino acid sequence of β (β(1-16)PEG). Our results demonstrate for the first time that the Aβ(1 -16) is able to coordinate up to three zinc Ions, all the histldyl residues acting as Independent anchor sites. The study was complemented by systematically Investigating the zinc(II) complexes of a series of shorter peptide fragments related to the Aβ(1-16) sequence, namely, Aβ(1-4), Aβ(1 -6), AcAβ(I-O), AcAβ(8-16)Y10A. The comparison of the whole results allowed the identification of the zinc(ll) preferred binding sites within the longer Aβ(1-16) amino acid sequence. Unlike copper(II) that prefers the N-termlnal amino group as the main binding site, the zinc(II) is preferentially placed In the 8-16 amino acidic region of Aβ(1-16).

Original languageEnglish
Pages (from-to)10405-10415
Number of pages11
JournalInorganic Chemistry
Volume48
Issue number21
DOIs
Publication statusPublished - Nov 2 2009

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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