Study on the interaction of the antiviral drug, zidovudine with DNA using neutral red (NR) and methylene blue (MB) dyes

The interaction between the drug, zidovudine and calf thymus DNA (CT-DNA) in physiological buffer (pH 7.4) was investigated using neutral red (NR) and methylene blue (MB) dyes as a spectral probes by UV–vis absorption and fluorescence spectroscopy, as well as circular dichroism (CD) spectroscopy. The experimental results showed that the conformational changes in DNA helix induced by zidovudine are the reason for the fluorescence quenching of the DNA-NR system. In addition, by increasing zidovudine to DNA-MB solution, the fluorescence has no change. From the experimental results, it was found that zidovudine can cause structural changes on CT-DNA and bind with DNA via groove binding mode. At the same time, the paper proved that conformational changes of DNA can also lead to the fluorescence decrease of DNA-probe systems.