171506-31-3Relevant academic research and scientific papers
Short polyglutamine peptide forms a high-affinity binding site for thioflavin-T at the N-terminus
Matsuoka, Shigeru,Murai, Motoki,Yamazaki, Toshio,Inoue, Masayuki
, p. 5787 - 5790 (2012/08/28)
Thioflavin-T is one of the most important amyloid specific dyes and has been used for more than 50 years; however, the molecular mechanism of staining is still not understood. Chemically synthesized short polyglutamine peptides (Qn, n = 5-10) were subjected to the thioflavin-T (ThT) staining assay. It was found that the minimum Qn peptide that stained positive to ThT was Q6. Two types of ThT-binding sites, a high-affinity site (kd1 = 0.1-0.17 μM) and a low-affinity site (kd2 = 5.7-7.4 μM), were observed in short polyQs (n = 6-9). 13C{ 2H}REDOR NMR experiments were carried out to extract the local structure of ThT binding sites in Q8 peptide aggregates by observing the intermolecular dipolar coupling between [3-Me-d3]ThT and natural abundance Q8 or residue-specific [1,2-13C2] labeled Q8s. 13C{2H}REDOR difference spectra of the [3-Me-d3]ThT/natural abundance Q8 (1/9) complex indicated that all of the five carbons of the glutamine residue participated in the formation of ThT-binding sites. 13C{2H}DQF-REDOR experiments of [3-Me-d3]ThT/residue-specific [1,2-13C 2] labeled Q8 (1/50) complexes demonstrated that the N-terminal glutamine residue had direct contact with the ThT molecule at the high-affinity ThT-binding sites.
