Files
Abstract
Nickel superoxide dismutase (NiSOD) is a redox-active, Ni-containing metalloenzyme that disproportionates superoxide to O2 and H2O2 at a diffusion-limited rate. The unique NpeptideNamineS2cysteinate planar donors and loosely bound NHis axial donor enables NiSOD to perform chemistry with reactive oxygen species despite its oxygen-sensitive ligands. This has driven synthetic efforts at modelling the active site to better understand the structure-function relationship of NiSOD. To this end, this work presents the fourth generation of five-coordinate NiN3S2 complex from our group, [Ni(N3S2NMeIm)]– (1), that features an electronically and structurally accurate 1-methylimidazole (NMeIm) axial donor that is expectated to promote 5C Ni2+ with a long Ni---Naxial bond that is poised for functionality. Characterization of 1 is very similar to prior models however, its reactivity with oxidants suggests an enhanced electronic structural similarity to NiSOD, emphasizing the role of the axial donor as well as secondary protein structure on the functionality of NiSOD.