Interaction with DNA

The evolution of the UV/Vis spectum of the Tröger's Base analogue in the presence of increasing concentrations of DNA appeared almost identical to the changes induced by protonation of the molecule in acidic medium. This result would indicate a change in the protonation equilibrium of the basic molecule due to the interaction with DNA, which acts as an acidic macromolecule as proposed by Lamm and coll.

Comparison of the circular dichroism spectra measured in the presence of CT-DNA and in 3M HCl solution leads to the same conclusion. The spectra were also recorded for each enriched enantiomer. In each case very large changes were observed and characterized by the appearance of an intense band either positive or negative (depending on the enantiomer considered) centered respectively at 488 nm and 483 nm. The shapes of the curves are slightly different which may be indicative of configuration dependent modes of interaction. For both enantiomers the spectra resemble those of the protonated species in line with the UV observations. The magnitude of the induced CD spectra measured for (-)-TB is slightly greater than that observed with (+)-TB. This could be indication of preferential binding of (-)-TB with DNA.


Evolution of the UV/Vis spectra of the Tröger's Base analogue in the presence of DNA

Comparison of the evolution of circular dichroism spectra of the Tröger's Base analogue

[Summary] [Introduction] [Synthesis] [Physico...] [Enantioselective...] [Conclusion]