Hydrogenase iron-only

Tard C, Liu XM, Ibrahim SK, Bruschi M, Gioia LD, Davies SC, Yang X, Wang LS, Sawers G, Pickett CJ. 2005. Synthesis of the H-cluster framework of iron-only hydrogenase. Nature 433 610-613. 

Liu X, Ibrahim SK, Tard C, Pickett CJ. 2005. Iron-only hydrogenase Synthetic, structural and reactivity studies of model compounds. Coord Chem Rev 249 1641-1652. 

Lemon, B. J. and Peters, J. W. (1999) Binding of exogenously added carbon monoxide at the active site of the iron-only hydrogenase (CpI) from Clostridium pasteurianum. Biochemistry, 38, 12969-73. 

In vitro studies established that electrons are transferred efficiently from both NiFe- and iron-only hydrogenases to cytochrome C3. This small 13 kDa c-type cytochrome has four hemes (reduction potential -200 to -300 mV)... 

Pereira et al. (1998) provided biochemical evidence that electron transfer from either iron-only or NiFe-hydrogenases to HmcA is possible, although at a slow rate. The increase in electron-transfer rate by addition of cytochrome C3 indicates that a more probable electron-transport path is from hydrogen through hydrogenase and cytochrome C3 to HmcA. 

Iron-only hydrogenases have been isolated from several microorganisms [20, 21] and shown to be able both to produce and to consume dihydrogen. 

More complex assemblies of iron and sulfur, sometimes extended to other metals like nickel, molybdenum, vanadium, or other iron centers are found in some enzymes, that catalyze the transformation of small molecules [1, 14]. Among these centers, we will focus next on the P cluster and the FeMo cofactor of nitrogenase and on the H cluster of the iron-only hydrogenase. 

A light-driven compound containing a photosensitizing tetraphenylporphyrin group linked to a diiron azadithiolate moiety (25) has been synthesized as a model compound of iron-only hydrogenases. This compound reduces protons photochemically to hydrogen.392... 

Dithiocarbamates, in Ru and Os half-sandwiches, 6, 493 Dithiocarbenes, Pt complexes, 8, 439 Dithiocarboxy ligands, in molybdenum carbonyls, 5, 447 Dithiolate-bridged compounds in dinuclear iron compounds with Fe-Fe bonds, 6, 238 as iron-only hydrogenase biomimetic models, 6, 239 Dithiolate diamides, with Zr(IV), 4, 784 Dithiolene—uranium complexes, synthesis and characterization, 4, 212 Ditopic receptors, characteristics, 12, 489 Ditungsten complexes, associated reactions, 5, 748 Divinyllead diacetates... 

Iron-only hydrogenase, dithiolate-bridged compounds as biomimetic models, 6, 239 Iron oxide films, synthesis, 12, 51 Iron-palladium nanoparticles, preparation, 12, 74 Iron-platinum bimetallic clusters, with isocyanide clustes,... 

Peters JW (1999) Structure and mechanism of iron-only hydrogenases. Curr. Opin. Struct. Biol. 

The actual catalytic cycle of [NiFe] hydrogenase encompasses only three states Ni-SIa, Ni-C and Ni-R, which are interconverted by one-electron/one-proton equilibria (Figure 3.4.7A) [123, 124], In the catalytic process, the approaching H2 is attached to the Ni, and the bond is polarized followed by base-assisted heterolytic cleavage of the H2 molecule leading to a bridging hydride species. One of the candidates for acting as a base is a terminal cysteine at the Ni. Alternatively, a water molecule bound to the iron has been proposed [120]. Concomitant electron transfer to the proximal FeS cluster then leads to the Ni-C state, which has been shown to... 

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