Polyanion induced circular dichroism of Thioflavin T.

Thioflavin T (ThT) is amyloid specific fluorescence dye possessing the properties of molecular rotor. We have shown that Thioflavin T forms complexes with non-peptide polyanions heparin, polyadenylate and polystyrene sulphonate by means of absorption spectroscopy. In the presence of chiral polyanions - heparin and polyadenylate - induced optical activity of ThT occurs whereas interaction with achiral polystyrene sulphonate (PSS) does not lead to production of induced circular dichroism signal. The positively charged ThT forms centre for ordered binding of chiral polyanion. Similarly, complexation of structurally different chromophore 9-aminoacridine with polyanions has led to induction of optical activity only in the presence of chiral ones. We suggest that, primarily, the optical activity of environment plays important role in inducing optical activity of achiral compounds.