Interactions of an Artificial Zinc Finger Protein with Cd(II) and Hg(II): Competition and Metal and DNA Binding

Cys2His2 zinc finger proteins are important for living organisms, as they—among other functions—specifically recognise DNA when Zn(II) is coordinated to the proteins, stabilising their ??? secondary structure. Therefore, competition with metal ions may alter original function. Toxic such Cd(II) or Hg(II) might be especially dangerous because of similar chemical properties Zn(II). Most studies carried out so far have involved small peptides. we investigated interactions toxic a consisting three units and consequences on binding protein. Binding one per subunit protein was shown by circular dichroism spectroscopy, fluorimetry electrospray ionisation mass spectrometry. stabilised structure that Zn(II)-bound but slightly lower affinity. In contrast, could displace quantitatively (log?? ? 16.7), demolishing structure, further also observed. Based electrophoretic gel mobility shift assays, Cd(II)-bound specific target sequence similarly Zn(II)-loaded form ~0.6 log stability constant, while destroy completely.