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Updated: May 11, 2026

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Modification of amyloid-β1-42 fibril structure by methionine-35 oxidation
Liming Hou1, Hyoung-Gon Lee, Fang Han
1Abbott Vascular Inc., Menlo Park, CA, USA.
Oxidation of methionine-35 in amyloid-beta peptides alters the structure and stability of amyloid plaques. This finding links oxidative stress and Alzheimer's disease plaque formation, impacting neurotoxicity.
Area of Science:
- Neuroscience
- Biochemistry
- Pathology
Background:
- Alzheimer's disease (AD) involves oxidative stress and amyloid-beta (Aβ) plaque formation.
- The methionine-35 (Met35) residue of Aβ is crucial in AD's oxidative stress and neurotoxicity.
- Previous studies showed Met35 oxidation inhibits Aβ assembly into protofibrils.
Purpose of the Study:
- To investigate how Met35 oxidation state affects the stability of pre-existing amyloid fibrils and plaques.
- To determine the impact of Met35 oxidation on the morphology of AD pathological structures.
Main Methods:
- Studied the effect of Met35 oxidation (Met35red → Met35ox) on isolated amyloid fibrils and senile plaques from AD patient brains.
- Analyzed morphological changes in filaments, protofibrils, and mature fibrils.
- Assessed Congo red birefringence in senile plaques.
Main Results:
- Met35 oxidation altered the morphology of amyloid structures, including fibrils, protofibrils, and mature fibrils.
- Oxidation led to a loss of Congo red birefringence in senile plaques.
- Fibrils exhibited increased flexibility, changing from straight to irregularly shaped, rope-like structures.
Conclusions:
- The oxidation state of Met35 significantly impacts the stability and morphology of existing amyloid plaques.
- Findings suggest a strong link between Met35 oxidation and the formation and characteristics of amyloid plaques in Alzheimer's disease.
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