An Iridium(III) Complex as a Photoactivatable Tool for Oxidation of Amyloidogenic Peptides with Subsequent Modulation of Peptide Aggregation.

ABSTRACT: Aggregates of amyloidogenic peptides are involved in the pathogenesis of several degenerative disorders. Herein, an iridium(III) complex, Ir-1, is reported as a chemical tool for oxidizing amyloidogenic peptides upon photoactivation and subsequently modulating their aggregation pathways. Ir-1 was rationally designed based on multiple characteristics, including 1)?photoproperties leading to excitation by low-energy radiation; 2)?generation of reactive oxygen species responsible for peptide oxidation upon photoactivation under mild conditions; and 3)?relatively easy incorporation of a ligand on the IrIII center for specific interactions with amyloidogenic peptides. Biochemical and biophysical investigations illuminate that the oxidation of representative amyloidogenic peptides (i.e., amyloid-?, ?-synuclein, and human islet amyloid polypeptide) is promoted by light-activated Ir-1, which alters the conformations and aggregation pathways of the peptides. Additionally, their potential oxidation sites are identified as methionine, histidine, or tyrosine residues. Overall, our studies on Ir-1 demonstrate the feasibility of devising metal complexes as chemical tools suitable for elucidating the nature of amyloidogenic peptides at the molecular level, as well as controlling their aggregation.

SUBMITTER: Kang J 

PROVIDER: S-EPMC5828235 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature