ИСТИНА

Amyloid fibrils are insoluble protein aggregates deposition of which accompanies a range of serious diseases, e.g. Alzheimer's and Parkinson's diseases, type II diabetes and Creutzfeldt-Jakob disease. Benzothiazole dye thioflavin T (ThT) is widely used for diagnostics of amyloid fibril formation in vivo and in vitro due to the unique property of this dye to form highly fluorescent complexes with amyloid and amyloid-like fibrils. It has now become evident that ThT can also be used for structural investigations of amyloid fibrils and even for treatment of amyloid diseases. In this connection, our work is devoted to elaboration an approach for accurate determination of ThT–amyloid fibril binding parameters and characteristics of bound dye: the number of binding modes; stoichiometry and binding constant for each mode; absorption spectrum and molar extinction coefficient for ThT bound to the sites of each mode. The proposed approach was used for examination of ThT interaction with lysozyme, insulin, Aβ42 peptid and β2-microglobulin amyloid fibrils. Obtained characteristics of ThT – amyloid fibril interaction can be used for studying and comparing the structure of amyloid fibrils formed by different amyloidogenic proteins.