In this study, the interaction of the anthracycline antibiotic doxorubicin
with DNA-HMG 1 complex was investigated employing UV/VIS spectroscopy,
thermal denaturation and DNA cellulose chromatography techniques. The
results indicated that the binding of doxorubicin to the protein reduces its Tm
in a dose dependent manner. Although doxorubicin protects free DNA
against thermal denaturation in the presence of HMG 1, thermal melts represent
biphasic profile corresponding to DNA- drug, HMG1- drug and free
components. Interaction of antibiotic with DNA - HMGl complex using
DNA cellulose columns also implies that the drug binds strongly to singlestranded
DNA-HMG 1 complex rather than to double- stranded DNA-HMG 1
columns. The results suggest destabilization of HMGl protein by drug action
thereby preventing DNA-HMG 1 complex formation