Studies of Interaction Between Cyanine Dye T-284 and Fibrillar Alpha-Synuclein

Kateryna D. Volkova, Vladyslava B. Kovalska, Mykhaylo Yu. Losytskyy, G.J. Veldhuis, G. Veldhuis, Gezina M.J. Segers-Nolten, Olexiy I. Tolmachev, Vinod Subramaniam, Sergiy M. Yarmoluk

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A key feature of Parkinson’s disease is the formation and accumulation of amyloid fibrils of the natively unfolded protein α-synuclein (ASN) inside neurons. Recently we have proposed novel sensitive monomethinecyanine dye T-284 as fluorescent probe for quantitative detection of ASN amyloid fibrils. In this study the T-284 dye complex with ASN fibril was characterized by means of fluorescence anisotropy, atomic force microscopy and time-resolved fluorescence techniques to give further insights into the mode of dye interaction with amyloid fibrils. The fluorescence anisotropy of T-284 was shown to noticeably increase upon addition of aggregated proteins indicating on stable dye/amyloid fibril complex formation. AFM imaging of fibrillar wild-type ASN revealed differences in heights between ASN fibrils alone and in presence of the T-284 dye (6.37 ± 1.0 nm and 8.0 ± 1.1 nm respectively), that is believed to be caused by embedding of T-284 dye molecules in the “binding channel” running along the fibril. Fluorescence decay analysis of the T-284 in complexes with fibrillar ASN variants revealed the fluorescence lifetime values for T-284/fibril complexes to be an order of magnitude higher as compared to the free dye. Also, the fluorescence decay of free T-284 was bi-exponential, while dye bound to protein yields tri-exponential decay. We suppose that in complexes with fibrillar ASN variants T-284 dye might exist in different “populations” due to interaction with fibrils in different conformers and ways. The exact binding mode of T-284 with ASN fibrils needs further studies. Studied parameters of dye/amyloid fibril complexes are important for the characterization and screening of newly-developed amyloid-sensitive dyes.
Original languageUndefined
Pages (from-to)1267-1274
JournalJournal of fluorescence
Issue number6
Publication statusPublished - 2010


  • Cyanine dyes - α-synuclein - Amyloid fibrils - Fluorescent detection - Atomic force microscopy
  • METIS-268279
  • IR-77901

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