title: Trimethine cyanine dyes as fluorescent probes for amyloid fibrils: The effect of N,N'-substituents.
abstract: The effect of various N,N'-substituents in the molecule of benzothiazole trimethine cyanine dye on its ability to sense the amyloid aggregates of protein was studied. The dyes are low fluorescent when free and in the presence of monomeric proteins, but their emission intensity sharply increases in complexes with aggregated insulin and lysozyme, with the fluorescence quantum yield reaching up to 0.42. The dyes carrying butyl, hydroxyalkyl, and phenylalkyl groups as N,N'-substituents possess the increased fluorescent sensitivity to fibrillar lysozyme, whereas the ones carrying quaternary amino groups are preferably sensitive to fibrillar insulin. This fluorescent sensitivity preference provided by the N,N'-functional groups could be explained by the interaction between these groups and protein side chains. The strongest fluorescent response (up to 70times) and the same sensitivity to aggregates of both proteins were exhibited by the dye D-51 carrying N-sulfoalkyl group. The studied cyanines allow the detection of fibrillar aggregates in the wide range up to 0.8 to 300μg/ml and permit monitoring the protein aggregation kinetics with high reproducibility. The modification of trimethine cyanine dyes by functional substituents in N,N'-positions is suggested as a tool for the design of fluorescent molecules with the enhanced fluorescent sensitivity to the fibrillar aggregates of proteins.
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine.
authors.forename: Marina V
authors.initials: MV
authors.lastname: Kuperman
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine.
authors.forename: Svitlana V
authors.initials: SV
authors.lastname: Chernii
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine. Electronic address: mlosytskyy@gmail.com.
authors.forename: Mykhaylo Yu
authors.initials: MY
authors.lastname: Losytskyy
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine.
authors.forename: Dmytro V
authors.initials: DV
authors.lastname: Kryvorotenko
authors.affiliation: Institute of Organic Chemistry, National Academy of Sciences of Ukraine (NASU), 02094 Kyiv, Ukraine.
authors.forename: Nadiya O
authors.initials: NO
authors.lastname: Derevyanko
authors.affiliation: Institute of Organic Chemistry, National Academy of Sciences of Ukraine (NASU), 02094 Kyiv, Ukraine.
authors.forename: Yurii L
authors.initials: YL
authors.lastname: Slominskii
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine.
authors.forename: Vladyslava B
authors.initials: VB
authors.lastname: Kovalska
authors.affiliation: Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine (NASU), 03143 Kyiv, Ukraine.
authors.forename: Sergiy M
authors.initials: SM
authors.lastname: Yarmoluk
mesh_terms: D000682:Amyloid / Q000032:analysis / Q000737:chemistry*; D002021:Buffers; D002232:Carbocyanines / Q000737:chemistry*; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000032:analysis / Q000737:chemistry; D007700:Kinetics; D057230:Limit of Detection; D009113:Muramidase / Q000032:analysis / Q000737:chemistry; D066329:Protein Aggregates; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship
chemical_list: D000682:Amyloid; D002021:Buffers; D002232:Carbocyanines; D005456:Fluorescent Dyes; D007328:Insulin; D066329:Protein Aggregates; D009113:Muramidase
keywords: Amyloid fibrils; Cyanine dyes; Fluorescent probes; Insulin; Lysozyme; Protein aggregation