SODs are critical metalloenzymes that catalyze the dismutation of superoxide to prevent oxidative damage to biomolecules. The recently discovered Ni-SOD provides a new role for Ni in biology. In the Ni2+ state, the square-planar Ni is coordinated to the N-terminal amine of His1, backbone amide-N of Cys2 and the thiolates of Cys2 and Cys6. In the Ni3+ state, the imidazole-N from His1 coordinates in an axial position resulting in an N3S2 square-pyramidal coordination framework. Prior work in our group revealed that NiN2S2 complexes reproduce the structural/electronic properties of Ni-SODred but was not sufficient to promote Ni3+ and SOD activity. In an effort to understand the role of this particular donor, we have now prepared N/S ligand constructs that replicate all aspects of the unusual coordination sphere present in Ni-SOD. Herein, we report the synthesis, structure and properties of Ni-SOD synthetic analogues that incorporate imidazole-N-donors in new N/S ligand frames.

Synthetic models of Ni-SOD employing imidazole N/S ligand constructs

244th National Meeting (2012)

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