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Issue 30, 2012
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Short polyglutamine peptide forms a high-affinity binding site for thioflavin-T at the N-terminus

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Abstract

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 [1,2-13C2] 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.

Graphical abstract: Short polyglutamine peptide forms a high-affinity binding site for thioflavin-T at the N-terminus

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Publication details

The article was received on 22 Dec 2011, accepted on 23 Feb 2012 and first published on 24 Feb 2012


Article type: Communication
DOI: 10.1039/C2OB07157F
Citation: Org. Biomol. Chem., 2012,10, 5787-5790
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    Short polyglutamine peptide forms a high-affinity binding site for thioflavin-T at the N-terminus

    S. Matsuoka, M. Murai, T. Yamazaki and M. Inoue, Org. Biomol. Chem., 2012, 10, 5787
    DOI: 10.1039/C2OB07157F

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