Cu²⁺ Effects on Beta‐Amyloid Oligomerisation Monitored by the Fluorescence of Intrinsic Tyrosine

Abstract

A non‐invasive intrinsic fluorescence sensing of the early stages of Alzheimer's beta amyloid peptide aggregation in the presence of copper ions is reported. By using time‐resolved fluorescence techniques the formation of beta amyloid‐copper complexes and the accelerated peptide aggregation are demonstrated. The shifts in the emission spectral peaks indicate that the peptides exhibit different aggregation pathways than in the absence of copper.

Non-fluorescent transient states of tyrosine as a basis for label-free protein conformation and interaction studies

“…Several peptides and smaller proteins of large biomedical relevance, such as A-beta peptides and alfa-synuclein, do not contain any Trp residues, but one or several Tyr residues, and their fluorescence has been useful to study structural and aggregation properties of e.g. beta-amyloid peptides and their role in Alzheimer´s disease and possible disease inhibitors 5 – 8 . Given the limited fluorescence brightness of Tyr, it is in studies of such peptides and proteins motivated to extract all possible information content in the emitted fluorescence, and time-resolved lifetime measurements have proven to add useful information to spectrofluorometer measurements 4 – 9 .…”