Kinetic studies of inhibition of the amyloid beta (1-42) aggregation using a ferrocene-tagged ?-sheet breaker peptide.

ABSTRACT: The aggregation of amyloidogenic proteins/peptides has been closely linked to the neuropathology of several important neurological disorders. In Alzheimer's disease, amyloid beta (A?) peptides and their aggregation are believed to be at least partially responsible for the etiology of Alzheimer's disease. The aggregate-inflicted cellular toxicity can be inhibited by short peptides whose sequences are homologous to segments of the A?(1-42) peptide responsible for ?-sheet stacking (referred to as the ?-sheet breaker peptides). Here, a water-soluble ferrocene (Fc)-tagged ?-sheet breaker peptide, Fc-KLVFFK(6), was used as an electrochemical probe for kinetic studies of the inhibition of the A?(1-42) fibrillation process and for determination of the optimal concentration of ?-sheet breaker peptide for efficient inhibition. Our results demonstrate that Fc-KLVFFK(6) interacts with the A? aggregates instantaneously in solution, and a sub-stoichiometric amount of Fc-KLVFFK(6) is sufficient to inhibit the formation of the A? oligomers and fibrils and to reduce the toxicity of A?(1-42). The interaction between Fc-KLVFFK(6) and A?(1-42) follows a pseudo-first-order reaction, with a rate constant of 1.89 ± 0.05 × 10(-4) s(-1). Tagging ?-sheet breaker peptides with a redox label facilitates design, screening, and rational use of peptidic inhibitors for impeding/altering A? aggregation.

SUBMITTER: Zhang L 

PROVIDER: S-EPMC3565064 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature