| Autor: |
Sulatskaya AI; Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology of the Russian Academy of Science , Tikhoretsky ave. 4 , St. Petersburg 194064 , Russia., Rychkov GN; Institute of Physics, Nanotechnology and Telecommunications , Peter the Great St.-Petersburg Polytechnic University , Polytechnicheskaya 29 , St. Petersburg 195251 , Russia.; Department of Molecular and Radiation Biophysics , Petersburg Nuclear Physics Institute, NRC Kurchatov Institute , Orlova Roscha, Gatchina, Leningrad District , 188300 , Russia., Sulatsky MI; Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology of the Russian Academy of Science , Tikhoretsky ave. 4 , St. Petersburg 194064 , Russia., Rodina NP; Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology of the Russian Academy of Science , Tikhoretsky ave. 4 , St. Petersburg 194064 , Russia.; Institute of Physics, Nanotechnology and Telecommunications , Peter the Great St.-Petersburg Polytechnic University , Polytechnicheskaya 29 , St. Petersburg 195251 , Russia., Kuznetsova IM; Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology of the Russian Academy of Science , Tikhoretsky ave. 4 , St. Petersburg 194064 , Russia., Turoverov KK; Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology of the Russian Academy of Science , Tikhoretsky ave. 4 , St. Petersburg 194064 , Russia.; Institute of Physics, Nanotechnology and Telecommunications , Peter the Great St.-Petersburg Polytechnic University , Polytechnicheskaya 29 , St. Petersburg 195251 , Russia. |
| Abstrakt: |
The aim of the present work was investigation of the fluorescent dye thioflavin T (ThT) binding to acetylcholinesterase (AChE). ThT is an effective test for protease activity, as well as a probe for amyloid fibril formation. Despite the extended and active investigation of ThT-AChE binding, there is still no common view on the stoichiometry of this interaction. In particular, there is a hypothesis explaining the spectral properties of bound to AChE dye and high quantum yield of its fluorescence by formation of dimers or excimers of ThT. In order to confirm or deny this hypothesis, we proposed a new experimental approach for examination of ThT-AChE interaction based on spectroscopic investigation of samples prepared by equilibrium microdialysis. This approach allowed us to prove 1/1 ThT/AChE binding stoichiometry. The increase of ThT fluorescence quantum yield and lifetime accompanying its binding to AChE can be explained by the molecular rotor nature of this dye. Together with the coincidence of the positions of free and AChE-bound ThT fluorescence spectra, the obtained results prove the groundlessness of the hypotheses about ThT aggregation while binding to AChE. The model of ThT localization in the active site of AChE was proposed by using molecular docking simulations. These results also allowed us to suggest the key role of aromatic residues in ThT-AChE interaction, as observed for some amyloid fibrils. |
