A spectroscopic study of 2-[4'-(dimethylamino)phenyl]-benzothiazole binding to insulin amyloid fibrils

  • J Fluoresc. 2010 Jul;20(4):881-9. doi: 10.1007/s10895-010-0634-0.
Catherine C Kitts  1 ,  David Anton Vanden Bout
Affiliations
  • 1. Department of Chemistry and Biochemistry, Center for Nano and Molecular Science and Technology, and Texas Materials Institute, University of Texas at Austin, Austin, TX 78712, USA.
PMID: 20204681 DOI: 10.1007/s10895-010-0634-0
Abstract

The spectroscopic properties of 2-[4'-(dimethylamino)phenyl]-benzothiazole (BTA-2) in solution and in the presence of amyloid fibrils were investigated using absorption and fluorescence spectroscopy. Solution studies show that BTA-2 forms micelles in aqueous solutions, but that the dye can be solvated upon the addition of acetonitrile (CH(3)CN). BTA-2 binds to amyloid fibrils in solution leading to a characteristic blue-shift in the emission spectrum and an increase in fluorescence intensity. However, in solutions with increasing CH(3)CN concentration, there was a marked decrease in binding of the BTA-2 to fibrils. Studies demonstrating the effect of BTA-2 concentration on binding were performed. A comparison with the standard amyloid fluorescent marker, thioflavin T (ThT), showed that BTA-2 is more fluorescent, making it an excellent dye to label amyloid samples.

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