Spectrometric Studies on Interaction Between Metal Ions and DNA-Binding Domain of Tumor Suppressor Protein p53
Abstract Site-specific recognition and DNA-binding activity of tumor suppressor protein p53 are crucial for its tumor suppressor function. Previous reports have shown that metal ions could affect specific recognition and DNA-binding activity of p53 DNA-binding domain (p53DBD). In this study, we investigated the binding reaction between p53DBD and nine kinds of metal ions by fluorescence titration method, the binding affinity of metal ions to p53DBD is Fe 3+ > Zn 2+ > Cu 2+ > Ca 2+ > Mg 2+ > Ba 2+ > Mn 2+ > Ni 2+ > Co 2+ . Analysis of the far-UV CD data suggested that the binding of Ba 2+ , Ca 2+ , Co 2+ , Mn 2+ and Ni 2+ did not induce changes in protein secondary structure. The binding of Zn 2+ , Mg 2+ and Fe 3+ induced a subtle conformational change, whereas the binding of Cu 2+ resulted in a lot of loss in its helical content. Analysis of 8-anilino-1-naphthalenesulfonic acid binding data showed that the binding of Mg 2+ enhanced hydrophobic exposure on protein surface such as Zn 2+ , whereas Fe 3+ decreased hydrophobic exposure. Therefore, Mg 2+ and Fe 3+ may be one of potential factors to affect or regulate the transactivation of p53.