NiFe hydrogenase active site

Volbeda A, Garcin E, Piras C, et al. 1996. Structure of the [NiFe] hydrogenase active site evidence for biologically uncommon Fe ligands. J Am Chem Soc 118 12989-96. 

Bruschi M, De Gioia L, Zampella G, Reiher M, Fantucci P, Stein M,(2004). A theoretical study of spin states in Ni-S4 complexes and models of the [NiFe] hydrogenase active site. J. Biol. Inorg. Chem. 9 873-884... 

Barton BE, Whaley CM, Rauchfuss TB, Gray DF. Nickel-iron dithiolato hydrides relevant to the [NiFe]-hydrogenase active site. J Am Chem Soc. 2009 131(20) 6942-3. 

The spatial arrangement of the Fe-S clusters in D. gigas NiFe-hydrogenase (see Fig. 1) suggests an active role for the [Fe3S4] ° cluster in mediating electron transfer from the NiFe active site to the... 

The biologically uncommon Ni center associated with FeS clusters is a powerful and unique catalytic unity. In this chapter we have reviewed the structural and mechanistic aspects of three NiFeS centers the active site of hydrogenase and Clusters A and C of CODH/ACS. In the former, the association of a Ni center with the most unusual FeCOCN2 unit is a fascinating one. Model chemists, spectroscopists, and crystallographers have joined efforts to try and elucidate the reaction mechanism. Although a consensus is being slowly reached, the exact roles of the different active site components have not yet been fully established. Ni appears to be the catalytic center proper, whereas the unusual Fe center may be specially suited to bind a by-... 

The [NiFe] hydrogenase from D. gigas has been used as a prototype of the [NiFe] hydrogenases. The enzyme is a heterodimer (62 and 26 kDa subunits) and contains four redox active centers one nickel site, one [3Fe-4S], and two [4Fe-4S] clusters, as proven by electron paramagnetic resonance (EPR) and Mosshauer spectroscopic studies (174). The enzyme has been isolated with different isotopic enrichments [6 Ni (I = I), = Ni (I = 0), Fe (I = 0), and Fe (I = )] and studied after reaction with H and D. Isotopic substitutions are valuable tools for spectroscopic assignments and catalytic studies (165, 166, 175). 

A crystallographic analysis of xenon binding to [NiFe] hydrogenase, together with a molecular dynamic simulation study of xenon and dihydrogen diffusion in the enzyme interior, suggests the existence of hydrophobic channels connecting the molecular surface with the active site 184). 

Fig. 6 The models for the active site of [FeFe]-, [NiFe]-, and [Fe]-hydrogenases...

Wang C-P, R Franco, JJG Moura, 1 Moura, EP Day (1992) The nickel site in active Desulfovibrio baculatus [NiFeS] hydrogenase is diamagnetic. Multifield saturation magnetization measurement of the spin state of Ni(II). 7 Sio/ Chem 267 7378-7380. 

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