1. Interaction of thioflavin T with amyloid fibrils of apolipoprotein A-I N-terminal fragment: resonance energy transfer study.
- Author
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Girych M, Gorbenko G, Trusova V, Adachi E, Mizuguchi C, Nagao K, Kawashima H, Akaji K, Lund-Katz S, Phillips MC, and Saito H
- Subjects
- Benzothiazoles, Binding Sites, Energy Transfer, Humans, Protein Binding, Protein Interaction Domains and Motifs, Amyloid chemistry, Apolipoprotein A-I chemistry, Thiazoles chemistry
- Abstract
Apolipoprotein A-I is amenable to a number of specific mutations associated with hereditary systemic amyloidoses. Amyloidogenic properties of apoA-I are determined mainly by its N-terminal fragment. In the present study Förster resonance energy transfer between tryptophan as a donor and Thioflavin T as an acceptor was employed to obtain structural information on the amyloid fibrils formed by apoA-I variant 1-83/G26R/W@8. Analysis of the dye-fibril binding data provided evidence for the presence of two types of ThT binding sites with similar stoichiometries (bound dye to monomeric protein molar ratio ∼10), but different association constants (∼6 and 0.1μM(-1)) and ThT quantum yields in fibril-associated state (0.08 and 0.05, respectively). A β-strand-loop-β-strand structural model of 1-83/G26R/W@8 apoA-I fibrils has been proposed, with potential ThT binding sites located in the solvent-exposed grooves of the N-terminal β-sheet layer. Reasoning from the expanded FRET analysis allowing for heterogeneity of ThT binding centers and fibril polymorphism, the most probable locations of high- and low-affinity ThT binding sites were attributed to the grooves T16_Y18 and D20_L22, respectively., (Copyright © 2013 Elsevier Inc. All rights reserved.)
- Published
- 2014
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