JBIC Journal of Biological Inorganic Chemistry

, Volume 9, Issue 7, pp 873–884

A theoretical study of spin states in Ni-S4 complexes and models of the [NiFe] hydrogenase active site

  • Maurizio Bruschi
  • Luca De Gioia
  • Giuseppe Zampella
  • Markus Reiher
  • Piercarlo Fantucci
  • Matthias Stein
Original Article

DOI: 10.1007/s00775-004-0588-2

Cite this article as:
Bruschi, M., De Gioia, L., Zampella, G. et al. J Biol Inorg Chem (2004) 9: 873. doi:10.1007/s00775-004-0588-2

Abstract

We have applied density functional theory, using both pure (BP86) and hybrid (B3LYP and B3LYP*) functionals, to investigate structural parameters and reaction energies for nickel(II)-sulfur coordination compounds, as well as for small cluster models of the Ni-SI and Ni-R redox state of [NiFe] hydrogenases. Results obtained investigating experimentally well-characterized complexes show that BP86 is well suited to describe the structural features of this class of compounds. However, the singlet–triplet energy splitting and even the computed ground state are strongly dependent on the applied functional. Results for the cluster models of [NiFe] hydrogenases lead to the conclusion that in the reduced protein structures characterized by X-ray diffraction a hydride bridges the two metal centres. The energy splitting of the singlet and triplet states in Ni-R and Ni-SI models is calculated to be very small and may be overcome at room temperature to allow a spin crossover. Moreover, the relative stability of the Ni-SI and Ni-R structures adopted in the present investigation is fully compatible with their involvement in the reversible heterolytic cleavage of H2.

Keywords

Density functional theoryNickel-sulfur coordination compounds[NiFe] hydrogenases

Supplementary material

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Copyright information

© SBIC 2004

Authors and Affiliations

  • Maurizio Bruschi
    • 2
  • Luca De Gioia
    • 1
  • Giuseppe Zampella
    • 1
  • Markus Reiher
    • 3
  • Piercarlo Fantucci
    • 1
  • Matthias Stein
    • 4
  1. 1.Department of Biotechnology and BiosciencesUniversity of Milano-BicoccaMilanItaly
  2. 2.Department of Environmental ScienceUniversity of Milano-BicoccaMilanItaly
  3. 3.Lehrstuhl für Theoretische ChemieUniversität BonnBonnGermany
  4. 4.Anterio Research GmbHMannheimGermany