Mimicking acetyl-coenzyme A synthase

The carbon monoxide dehydrogenase acetyl Co-enzyme A synthase (CODH/ACS) is a bifunctional enzyme, which couples the reduction of CO2 to the conversion of CO, a methyl group and co-enzyme A (HSCoA) to give acetyl co-enzyme A (CH3C(O)SCoA).

Recent advances in X-ray crystallography have significantly contributed to the understanding of the active site, revealing two Ni centres linked to a [Fe4S4] cluster. Mechanistic questions that remain unresolved include the binding sequence, the electronic structure of the reduced di-nickel site (NiINiII or Ni0NiII or even a higher reduced state), and the influence of the [Fe4S4] cluster.

Assembly of a nickel(II) acyl moiety setting out from CO bound to nickel(0)

We have recently established the first example of a Ni-CO compound that is converted into a Ni-C(O)-CH3 complex by transfer of CH3+, indicating that CO binding may be the first event in the catalytic cycle, especially since subsequent C-S bond formation could be realised, too.

Research goals 

  • Future studies will aim at elucidating the dependence of the reactivity on the oxidation state of the Ni centre and the electronic structure of its surroundings, i.e., iron/sulphur or other appendices providing reducing equivalents.

  • Furthermore, novel functional dinuclear [NiNi] complexes will be synthesised and investigated.