Methionine oxidation reduces lag-times for amyloid-β(1-40) fiber formation but generates highly fragmented fibers

Copyright © 2016 Elsevier B.V. All rights reserved..

Oxidative stress and the formation of amyloid plaques containing amyloid-β (Aβ) peptides are two key hallmarks of Alzheimer's disease. A proportion of methionine (Met) at position 35 within Aβ is oxidized to methionine sulphoxide (Met(OX)) within the Alzheimer's plaques. These oxidative processes may be the key to understanding the early stages of Alzheimer's disease. In vitro oxidation of Aβ, by the physiological oxidant H2O2, was monitored using (1)H NMR and mass spectrometry. Here we investigate the effect of Aβ methionine oxidation on fiber formation kinetics and morphology using the amyloid specific fluorescence dye Thioflavin T (ThT) and Transmission Electron Microscopy (TEM). Methionine oxidation reduces the total amount of fibers generated for both dominant forms of Aβ, however there are marked differences in the effect of Met(OX) between Aβ(1-40) and Aβ(1-42). Surprisingly the presence of Met(OX) reduces lag-times for Aβ(1-40) fiber formation but extends lag-times for Aβ(1-42). TEM indicates a change in fiber morphology with a pronounced reduction in fiber length for both methionine oxidized Aβ(1-40) and Aβ(1-42). In contrast, the morphology of preformed amyloid fibers is largely unaffected by the presence of H2O2. Our studies suggest that methionine oxidation promotes highly fragmented fiber assemblies of Aβ. Oxidative stress associated with Alzheimer's disease can cause oxidation of methionine within Aβ and this in turn will influence the complex assembly of Aβ monomer into amyloid fibers, which is likely to impact Aβ toxicity.

Medienart:

E-Artikel

Erscheinungsjahr:

2016

Erschienen:

2016

Enthalten in:

Zur Gesamtaufnahme - volume:1864

Enthalten in:

Biochimica et biophysica acta - 1864(2016), 9 vom: 01. Sept., Seite 1260-1269

Sprache:

Englisch

Beteiligte Personen:

Gu, Miao [VerfasserIn]
Viles, John H [VerfasserIn]

Links:

Volltext

Themen:

2390-54-7
AE28F7PNPL
Alzheimer's
Amyloid
Amyloid beta-Peptides
Amyloid beta-protein (1-40)
Amyloid beta-protein (1-42)
BBX060AN9V
Benzothiazoles
Fiber
Hydrogen Peroxide
Journal Article
Kinetics
Methionine
Methionine sulfoxide
Oxidation
Peptide Fragments
Research Support, Non-U.S. Gov't
Solutions
Thiazoles
Thioflavin T
XN1XVI4B2C

Anmerkungen:

Date Completed 04.10.2017

Date Revised 10.12.2019

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.bbapap.2016.04.009

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM259687359