DNA بررسي برهم كنش كافيين با ملكول

study of the interaction of caffeine with DNA

Caffeine is one of the most widely consumed drugs in the world and it is used in treatment of asthma and apnea of newborn babies. Caffeine, possibly because of itʹs structural relation to pure bases in nucleic acids, can bind to DNA. In this study, the interaction of caffeine with DNA was investigated employing spectroscopy, thermal denaturation, equilibrium dialysis and DNA cellulose chromatography techniques. The results show that the effect of caffeine is dose dependent. At low concentrations of caffeine (<1 mM), no significant changes, while at high concentrations of caffeine (>lmM), hypochromocity accompanied by red shift at 210 nm and blue shift at 260 nm was observed. The binding of caffeine to DNA reduces Tm of DNA by - 10 degree in a dose dependent manner. Binding isotherms obtained for the binding of caffeine to DNA represented a positive cooperativity with n values of 1.388. Hill curve showed two sites for the binding of drug to DNA. Hill constants were 2.553 and 1.123 and the binding constants were 10x 10"5 and 8.2 x 10ʹ8 respectively. Interaction of caffeine with DNA cellulose columns also implied that caffeine binds strongly to double-stranded DNA rather than to single-stranded DNA columns. The results suggest destabilization of DNA by high concentrations of caffeine, which may explain the biological role of caffeine at these concentrations in living cells.