FLUORESCENCE LIFETIME AND ANISOTROPY OF FREE AND BOUND TO AMYLOID FIBRILS THIOFLAVIN T
In the present work, fluorescence decay curves of benzothiazole dye, thioflavin T (ThT), in water-glycerol mixtures, under macromolecular crowding conditions simulating the densely populated cell medium and bound to insulin and yeast prion protein (Sup35NM) amyloid fibrils were studied. It was shown that the dye fluorescence anisotropy in solutions with high viscosity, in the presence of crowding agents and bound to amyloid fibrils, is extremely high and practically does not differ from that of ThT in water solution. At the same time, the fluorescence lifetimes of ThT bound to insulin and Sup35NMp fibrils differ from each other and several orders of magnitude longer than that in aqueous solutions. It was suggested that the obtained results are caused by ThT molecular rotor nature. On the basis of this work results, it was concluded that the measurement of the ThT fluorescence lifetime (but not its fluorescence anisotropy) can be used to study the kinetics of amyloid fibrils formation and their polymorphism.