A catalytic antioxidant for limiting amyloid-beta peptide aggregation and reactive oxygen species generation.

ABSTRACT: Alzheimer's disease (AD) is a multifaceted disease that is characterized by increased oxidative stress, metal-ion dysregulation, and the formation of intracellular neurofibrillary tangles and extracellular amyloid-? (A?) aggregates. In this work we report the large affinity binding of the iron(iii) 2,17-bis-sulfonato-5,10,15-tris(pentafluorophenyl)corrole complex FeL1 to the A? peptide (K d ? 10-7) and the ability of the bound FeL1 to act as a catalytic antioxidant in both the presence and absence of Cu(ii) ions. Specific findings are that: (a) an A? histidine residue binds axially to FeL1; (b) that the resulting adduct is an efficient catalase; (c) this interaction restricts the formation of high molecular weight peptide aggregates. UV-Vis and electron paramagnetic resonance (EPR) studies show that although the binding of FeL1 does not influence the A?-Cu(ii) interaction (K d ? 10-10), bound FeL1 still acts as an antioxidant thereby significantly limiting reactive oxygen species (ROS) generation from A?-Cu. Overall, FeL1 is shown to bind to the A? peptide, and modulate peptide aggregation. In addition, FeL1 forms a ternary species with A?-Cu(ii) and impedes ROS generation, thus showing the promise of discrete metal complexes to limit the toxicity pathways of the A? peptide.

SUBMITTER: Gomes LMF 

PROVIDER: S-EPMC6369440 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature