TY - JOUR
T1 - Interaction of Thioflavin T with amyloid fibrils of apolipoprotein A-I N-terminal fragment: Resonance energy transfer study
AU - Girych, Mykhailo
AU - Gorbenko, Galyna
AU - Trusova, Valeriya
AU - Adachi, Emi
AU - Mizuguchi, Chiharu
AU - Nagao, Kohjiro
AU - Kawashima, Hiroyuki
AU - Akaji, Kenichi
AU - Lund-Katz, Sissel
AU - Phillips, Michael C.
AU - Saito, Hiroyuki
PY - 2014/1
Y1 - 2014/1
N2 - 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 0.1 μM−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.
AB - 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 0.1 μM−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.
U2 - 10.1016/j.jsb.2013.10.017
DO - 10.1016/j.jsb.2013.10.017
M3 - Article
SN - 1047-8477
VL - 185
SP - 116
EP - 124
JO - Journal of Structural Biology
JF - Journal of Structural Biology
IS - 1
ER -